Digital broadcasting system and data processing method

ABSTRACT

A digital broadcasting system for transmitting/receiving a digital broadcasting signal and a data processing method are disclosed. A program table information has an identifier identifying mobile service data and main service data in a broadcasting signal. The program table information is multiplexed with the mobile service data and main service data. Then, broadcast receiving system can receive and output the mobile service data by parsing the program table information and using the identifier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a reissue application of U.S. Pat. No. 8,495,695,which issued on Jul. 23, 2013, from U.S. patent application Ser. No.13/053,125, filed on Mar. 21, 2011, which is a continuation of U.S.patent application Ser. No. 12/100,630, filed on Apr. 10, 2008, now U.S.Pat. No. 7,934,244, which claims the benefit of earlier filing date andright of priority to Korean Application No. 10-2007-0036562, filed onApr. 13, 2007, and also claims the benefit of U.S. Provisional PatentApplication Nos. 60/947,984, filed on Jul. 4, 2007, and 60/911,818,filed on Apr. 13, 2007, the contents of which are all herebyincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcasting system fortransmitting/receiving a digital broadcasting signal and a dataprocessing method.

2. Discussion of the Related Art

Among digital broadcasting schemes, since a vestigial sideband (VSB)transmission scheme which is employed as the digital broadcastingstandard in North America and Korea is a single carrier scheme,reception capability of a reception system may deteriorate in poorenvironments. In particular, since robustness for a channel variationand noise is further required in a portable or mobile broadcastingreceiver, reception capability may further deteriorate when mobile dataservice is transmitted by the VSB transmission scheme.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a digital broadcastingsystem and a data processing method that substantially obviate one ormore problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a digital broadcastingsystem and a data processing method, which are capable of improvingreception capability of a reception system by performing additionalencoding processes with respect to mobile service data and transmittingthe encoded mobile service data to the reception system.

Another object of the present invention is to provide a digitalbroadcasting system and a data processing method, which are capable ofimproving reception capability of a reception system by inserting knowndata into a predetermined region of a data region and transmitting thedata by an appointment of a transmitter and a receiver.

A further object of the present invention is to provide a digitalbroadcasting system and a data processing method, which are capable oftransmitting an identifier for identifying mobile service data and mainservice data.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adata processing method includes multiplexing program table information,which describes main service data and mobile service data and includesan identifier for identifying the main service data and the mobileservice data, with the mobile service data and the main service data. Anerror correction encoding process is performed with respect to themultiplexed mobile service data and the mobile service data, which issubjected to the error correction encoding process, and the main servicedata are multiplexed and then data packets are output. The data packetsare modulated and the modulated signal is transmitted.

The transmitting of the multiplexed signal may include multiplexing Themodulating and transmitting of the data packets includes arranging thedata packets in an unit of a data group and interleaving the datapackets by the unit of the data group, outputting a broadcasting signalobtained by modulating the interleaved broadcasting data andtransmitting the output broadcasting signal

According to another aspect of the present invention, a data processingmethod includes receiving a broadcasting signal in which main servicedata and mobile service data are multiplexed in an unit of a data group,obtaining program table information, which describes the main servicedata and the mobile service data and includes an identifier foridentifying the main service data and the mobile service, from thereceived broadcasting signal.

The obtained program table information is parsed and program informationof the mobile service data is obtained.

According to another aspect of the present invention, a digitalbroadcasting system includes a tuner receiving a broadcasting signal inwhich main service data and mobile service data are multiplexed in aunit of a data group, a demodulator demodulating the main service dataand the mobile service data from the broadcasting signal received by thetuner and outputting the demodulated data, a demultiplexerdemultiplexing program table information including an identifier foridentifying the main service data and the mobile service data, a videostream and an audio stream, in the demodulated data output from thedemodulator, a decoder decoding broadcasting contents according to thedemultiplexed video and audio streams, a program table informationdecoder decoding the demultiplexed program table information of themobile service data and a controller controlling the broadcastingcontents to be output according to the decoded program tableinformation.

When the program table information is at least one of a virtual channeltable (VCT) and a program map table (PMT), the identifier may be amodulation_mode field value in the program table information.

When the program table information is at least one of a virtual channeltable (VCT) and a program map table (PMT), the identifier may be aservice_type field value in the program table information.

When the program table information is a virtual channel table (VCT), theidentifier may be included in service_location_descriptor in the VCT.And when the program table information is a program mapping table (PMT),the identifier is included in a descriptor of the PMT.

And the controller may control power of the demodulator such that thedemodulator demodulates only a burst section including the broadcastingcontents.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a block diagram showing a digital broadcast transmittingsystem according to an embodiment of the present invention;

FIG. 2 is a detailed block diagram showing an example of the servicemultiplexer;

FIG. 3 is a block diagram showing an example of the transmitter;

FIG. 4 is a block diagram showing an example of the pre-processor ofFIG. 3;

FIG. 5 is a view showing an example of an RS frame encoding process;

FIGS. 6A and 6B are views showing the data structure of previous andnext stages of a data deinterleaver in a digital broadcast transmittingsystem according to the present invention;

FIG. 7 is a view showing a process of dividing an RS frame;

FIG. 8 is a view showing the operation of a packet multiplexer;

FIG. 9 is a detailed block diagram showing an example of a blockprocessor;

FIG. 10 is a detailed block diagram showing an example of a symbolencoder;

FIG. 11 is a view showing an example of a symbol interleaver;

FIG. 12A is a detailed block diagram showing an example of a blockprocessor;

FIG. 12B is a detailed block showing another example of the blockprocessor;

FIG. 13 is a view an example of aligning the output of a symbol-byteconverter within a block in accordance with a set standard;

FIG. 14 is a detailed block diagram showing an example of a trellisencoding module;

FIG. 15A is a view showing the block processor which is concatenatedwith the trellis encoding module;

FIG. 15B is a view showing another example of the block processor andthe trellis encoding module;

FIG. 16 is a block diagram showing an example of a block processor whichperforms an encoding process at a coding rate of 1/N;

FIG. 17 is a detailed block diagram showing a block processor accordingto another embodiment of the present invention;

FIG. 18 is a schematic diagram of a group formatter which receives atransmission parameter and inserts the received transmission parameterin a body region of a data group;

FIG. 19 is a block diagram showing an example of the block processorwhich receives the transmission parameter and processes the receivedtransmission parameter by the same process as the mobile service data;

FIG. 20 is a block diagram showing the structure of a packet formatterwhich is expanded so that the packet formatter can insert thetransmission parameter;

FIG. 21 is a block diagram showing a synchronization multiplexer whichis expanded in order to allow a transmission parameter to be inserted ina field synchronization segment region;

FIG. 22 is a block diagram showing a structure of a digital broadcastreceiving system according to an embodiment of the present invention;

FIG. 23 is a view showing an error correction decoding process of an RSframe decoder;

FIG. 24 is a view showing an example of transmitting program tableinformation for main service data and mobile service data

FIG. 25 is a view showing an example of a channel operation according toa program;

FIG. 26 is a conceptual view of programs provided as services in aphysical channel band;

FIG. 27 is a view showing an example of a program mapping table (PMT)for delivering an identifier of mobile service data;

FIG. 28 is a view showing a descriptor which can parse information foridentifying mobile/main service data;

FIG. 29 is a view showing an example of multiplexing the program tableinformation for the main service data and the mobile service data withbroadcasting data and transmitting the multiplexed data;

FIG. 30 is a view showing a virtual channel table (VCT) in the programtable information;

FIG. 31 is a view showing a modulation mode (modulation_mode) of thebroadcasting signal;

FIG. 32 is a view showing a service type (service_type) of thebroadcasting signal;

FIG. 33 is a view showing an example of generating the respective VCTsincluding the main service data and the mobile service data andtransmitting/receiving the VCTs;

FIG. 34 is a conceptual view of the reception of the mobile service dataincluded in a burst section while reducing power consumption;

FIG. 35 is a detailed view of FIG. 34;

FIG. 36 is a view showing an example of a broadcast receiving system;

FIG. 37 is a flowchart showing an example of receiving a broadcastingsignal;

FIG. 38 is a view showing a descriptor including an identifier of aburst section; and

FIG. 39 is a view showing an example of delivering cell information formobile reception.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. In addition,although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meaning of each term lying within.

Among the terms used in the description of the present invention, mainservice data correspond to data that can be received by a fixedreceiving system and may include audio/video (A/V) data. Morespecifically, the main service data may include A/V data of highdefinition (HD) or standard definition (SD) levels and may also includediverse data types required for data broadcasting. Also, the known datacorrespond to data pre-known in accordance with a pre-arranged agreementbetween the receiving system and the transmitting system. Additionally,in the present invention, mobile service data may include at least oneof mobile service data, pedestrian service data, and handheld servicedata, and are collectively referred to as mobile service data forsimplicity. Herein, the mobile service data not only correspond tomobile/pedestrian/handheld service data (M/P/H service data) but mayalso include any type of service data with mobile or portablecharacteristics. Therefore, the mobile service data according to thepresent invention are not limited only to the M/P/H service data.

The above-described mobile service data may correspond to data havinginformation, such as program execution files, stock information, and soon, and may also correspond to A/V data. Most particularly, the mobileservice data may correspond to A/V data having lower resolution andlower data rate as compared to the main service data. For example, if anA/V codec that is used for a conventional main service corresponds to aMPEG-2 codec, a MPEG-advanced video coding (AVC) or scalable videocoding (SVC) having better image compression efficiency may be used asthe A/V codec for the mobile service. Furthermore, any type of data maybe transmitted as the mobile service data. For example, transportprotocol expert group (TPEG) data for broadcasting real-timetransportation information may be serviced as the main service data.

Also, a data service using the mobile service data may include weatherforecast services, traffic information services, stock informationservices, viewer participation quiz programs, real-time polls & surveys,interactive education broadcast programs, gaming services, servicesproviding information on synopsis, character, background music, andfilming sites of soap operas or series, services providing informationon past match scores and player profiles and achievements, and servicesproviding information on product information and programs classified byservice, medium, time, and theme enabling purchase orders to beprocessed. Herein, the present invention is not limited only to theservices mentioned above. In the present invention, the transmittingsystem provides backward compatibility in the main service data so as tobe received by the conventional receiving system. Herein, the mainservice data and the mobile service data are multiplexed to the samephysical channel and then transmitted.

The transmitting system according to the present invention performsadditional encoding on the mobile service data and inserts the dataalready known by the receiving system and transmitting system (i.e.,known data), thereby transmitting the processed data. Therefore, whenusing the transmitting system according to the present invention, thereceiving system may receive the mobile service data during a mobilestate and may also receive the mobile service data with stabilitydespite various distortion and noise occurring within the channel.

General Description of a Transmitting System

FIG. 1 illustrates a block diagram showing a general structure of adigital broadcast transmitting system according to an embodiment of thepresent invention. Herein, the digital broadcast transmitting includes aservice multiplexer 100 and a transmitter 200. Herein, the servicemultiplexer 100 is located in the studio of each broadcast station, andthe transmitter 200 is located in a site placed at a predetermineddistance from the studio. The transmitter 200 may be located in aplurality of different locations. Also, for example, the plurality oftransmitters may share the same frequency. And, in this case, theplurality of transmitters receives the same signal. Accordingly, in thereceiving system, a channel equalizer may compensate signal distortion,which is caused by a reflected wave, so as to recover the originalsignal. In another example, the plurality of transmitters may havedifferent frequencies with respect to the same channel.

A variety of methods may be used for data communication each of thetransmitters, which are located in remote positions, and the servicemultiplexer. For example, an interface standard such as a synchronousserial interface for transport of MPEG-2 data (SMPTE-310M). In theSMPTE-310M interface standard, a constant data rate is decided as anoutput data rate of the service multiplexer. For example, in case of the8VSB mode, the output data rate is 19.39 Mbps, and, in case of the 16VSBmode, the output data rate is 38.78 Mbps. Furthermore, in theconventional 8VSB mode transmitting system, a transport stream (TS)packet having a data rate of approximately 19.39 Mbps may be transmittedthrough a single physical channel. Also, in the transmitting systemaccording to the present invention provided with backward compatibilitywith the conventional transmitting system, additional encoding isperformed on the mobile service data. Thereafter, the additionallyencoded mobile service data are multiplexed with the main service datato a TS packet form, which is then transmitted. At this point, the datarate of the multiplexed TS packet is approximately 19.39 Mbps.

At this point, the service multiplexer 100 receives at least one type ofmobile service data and program specific information (PSI)/program andsystem information protocol (PSIP) table data for each mobile serviceand encapsulates the received data to each transport stream (TS) packet.Also, the service multiplexer 100 receives at least one type of mainservice data and PSI/PSIP table data for each main service so as toencapsulate the received data to a TS packet. Subsequently, the TSpackets are multiplexed according to a predetermined multiplexing ruleand outputs the multiplexed packets to the transmitter 200.

Service Multiplexer

FIG. 2 illustrates a block diagram showing an example of the servicemultiplexer. The service multiplexer includes a controller 110 forcontrolling the overall operations of the service multiplexer, aPSI/PSIP generator 120 for the main service, a PSI/PSIP generator 130for the mobile service, a null packet generator 140, a mobile servicemultiplexer 150, and a transport multiplexer 160. The transportmultiplexer 160 may include a main service multiplexer 161 and atransport stream (TS) packet multiplexer 162. Referring to FIG. 2, atleast one type of compression encoded main service data and the PSI/PSIPtable data generated from the PSI/PSIP generator 120 for the mainservice are inputted to the main service multiplexer 161 of thetransport multiplexer 160. The main service multiplexer 161 encapsulateseach of the inputted main service data and PSI/PSIP table data to MPEG-2TS packet forms. Then, the MPEG-2 TS packets are multiplexed andoutputted to the TS packet multiplexer 162. Herein, the data packetbeing outputted from the main service multiplexer 161 will be referredto as a main service data packet for simplicity.

Thereafter, at least one type of the compression encoded mobile servicedata and the PSI/PSIP table data generated from the PSI/PSIP generator130 for the mobile service are inputted to the mobile servicemultiplexer 150. The mobile service multiplexer 150 encapsulates each ofthe inputted mobile service data and PSI/PSIP table data to MPEG-2 TSpacket forms. Then, the MPEG-2 TS packets are multiplexed and outputtedto the TS packet multiplexer 162. Herein, the data packet beingoutputted from the mobile service multiplexer 150 will be referred to asa mobile service data packet for simplicity. At this point, thetransmitter 200 requires identification information in order to identifyand process the main service data packet and the mobile service datapacket. Herein, the identification information may use valuespre-decided in accordance with an agreement between the transmittingsystem and the receiving system, or may be configured of a separate setof data, or may modify predetermined location value with in thecorresponding data packet. As an example of the present invention, adifferent packet identifier (PID) may be assigned to identify each ofthe main service data packet and the mobile service data packet.

In another example, by modifying a synchronization data byte within aheader of the mobile service data, the service data packet may beidentified by using the synchronization data byte value of thecorresponding service data packet. For example, the synchronization byteof the main service data packet directly outputs the value decided bythe ISO/IEC13818-1 standard (i.e., 0x47) without any modification. Thesynchronization byte of the mobile service data packet modifies andoutputs the value, thereby identifying the main service data packet andthe mobile service data packet. Conversely, the synchronization byte ofthe main service data packet is modified and outputted, whereas thesynchronization byte of the mobile service data packet is directlyoutputted without being modified, thereby enabling the main service datapacket and the mobile service data packet to be identified.

A plurality of methods may be applied in the method of modifying thesynchronization byte. For example, each bit of the synchronization bytemay be inversed, or only a portion of the synchronization byte may beinversed. As described above, any type of identification information maybe used to identify the main service data packet and the mobile servicedata packet. Therefore, the scope of the present invention is notlimited only to the example set forth in the description of the presentinvention.

Meanwhile, a transport multiplexer used in the conventional digitalbroadcasting system may be used as the transport multiplexer 160according to the present invention. More specifically, in order tomultiplex the mobile service data and the main service data and totransmit the multiplexed data, the data rate of the main service islimited to a data rate of (19.39-K) Mbps. Then, K Mbps, whichcorresponds to the remaining data rate, is assigned as the data rate ofthe mobile service. Thus, the transport multiplexer which is alreadybeing used may be used as it is without any modification. Herein, thetransport multiplexer 160 multiplexes the main service data packet beingoutputted from the main service multiplexer 161 and the mobile servicedata packet being outputted from the mobile service multiplexer 150.Thereafter, the transport multiplexer 160 transmits the multiplexed datapackets to the transmitter 200.

However, in some cases, the output data rate of the mobile servicemultiplexer 150 may not be equal to K Mbps. In this case, the mobileservice multiplexer 150 multiplexes and outputs null data packetsgenerated from the null packet generator 140 so that the output datarate can reach K Mbps. More specifically, in order to match the outputdata rate of the mobile service multiplexer 150 to a constant data rate,the null packet generator 140 generates null data packets, which arethen outputted to the mobile service multiplexer 150. For example, whenthe service multiplexer 100 assigns K Mbps of the 19.39 Mbps to themobile service data, and when the remaining (19.39-K) Mbps is,therefore, assigned to the main service data, the data rate of themobile service data that are multiplexed by the service multiplexer 100actually becomes lower than K Mbps. This is because, in case of themobile service data, the pre-processor of the transmitting systemperforms additional encoding, thereby increasing the amount of data.Eventually, the data rate of the mobile service data, which may betransmitted from the service multiplexer 100, becomes smaller than KMbps.

For example, since the pre-processor of the transmitter performs anencoding process on the mobile service data at a coding rate of at least½, the amount of the data outputted from the pre-processor is increasedto more than twice the amount of the data initially inputted to thepre-processor. Therefore, the sum of the data rate of the main servicedata and the data rate of the mobile service data, both beingmultiplexed by the service multiplexer 100, becomes either equal to orsmaller than 19.39 Mbps. Therefore, in order to match the data rate ofthe data that are finally outputted from the service multiplexer 100 toa constant data rate (e.g., 19.39 Mbps), an amount of null data packetscorresponding to the amount of lacking data rate is generated from thenull packet generator 140 and outputted to the mobile servicemultiplexer 150.

Accordingly, the mobile service multiplexer 150 encapsulates each of themobile service data and the PSI/PSIP table data that are being inputtedto a MPEG-2 TS packet form. Then, the above-described TS packets aremultiplexed with the null data packets and, then, outputted to the TSpacket multiplexer 162. Thereafter, the TS packet multiplexer 162multiplexes the main service data packet being outputted from the mainservice multiplexer 161 and the mobile service data packet beingoutputted from the mobile service multiplexer 150 and transmits themultiplexed data packets to the transmitter 200 at a data rate of 19.39Mbps.

According to an embodiment of the present invention, the mobile servicemultiplexer 150 receives the null data packets. However, this is merelyexemplary and does not limit the scope of the present invention. Inother words, according to another embodiment of the present invention,the TS packet multiplexer 162 may receive the null data packets, so asto match the data rate of the finally outputted data to a constant datarate. Herein, the output path and multiplexing rule of the null datapacket is controlled by the controller 110. The controller 110 controlsthe multiplexing processed performed by the mobile service multiplexer150, the main service multiplexer 161 of the transport multiplexer 160,and the TS packet multiplexer 162, and also controls the null datapacket generation of the null packet generator 140. At this point, thetransmitter 200 discards the null data packets transmitted from theservice multiplexer 100 instead of transmitting the null data packets.

Further, in order to allow the transmitter 200 to discard the null datapackets transmitted from the service multiplexer 100 instead oftransmitting them, identification information for identifying the nulldata packet is required. Herein, the identification information may usevalues pre-decided in accordance with an agreement between thetransmitting system and the receiving system. For example, the value ofthe synchronization byte within the header of the null data packet maybe modified so as to be used as the identification information.Alternatively, a transport_error_indicator flag may also be used as theidentification information.

In the description of the present invention, an example of using thetransport_error_indicator flag as the identification information will begiven to describe an embodiment of the present invention. In this case,the transport_error_indicator flag of the null data packet is set to‘1’, and the transport_error_indicator flag of the remaining datapackets are reset to ‘0’, so as to identify the null data packet. Morespecifically, when the null packet generator 140 generates the null datapackets, if the transport_error_indicator flag from the header field ofthe null data packet is set to ‘1’ and then transmitted, the null datapacket may be identified and, therefore, be discarded. In the presentinvention, any type of identification information for identifying thenull data packets may be used. Therefore, the scope of the presentinvention is not limited only to the examples set forth in thedescription of the present invention.

According to another embodiment of the present invention, a transmissionparameter may be included in at least a portion of the null data packet,or at least one table or an operations and maintenance (OM) packet (orOMP) of the PSI/PSIP table for the mobile service. In this case, thetransmitter 200 extracts the transmission parameter and outputs theextracted transmission parameter to the corresponding block and alsotransmits the extracted parameter to the receiving system if required.More specifically, a packet referred to as an OMP is defined for thepurpose of operating and managing the transmitting system. For example,the OMP is configured in accordance with the MPEG-2 TS packet format,and the corresponding PID is given the value of 0x1FFA. The OMP isconfigured of a 4-byte header and a 184-byte payload. Herein, among the184 bytes, the first byte corresponds to an OM_type field, whichindicates the type of the OM packet.

In the present invention, the transmission parameter may be transmittedin the form of an OMP. And, in this case, among the values of thereserved fields within the OM_type field, a pre-arranged value is used,thereby indicating that the transmission parameter is being transmittedto the transmitter 200 in the form of an OMP. More specifically, thetransmitter 200 may find (or identify) the OMP by referring to the PID.Also, by parsing the OM_type field within the OMP, the transmitter 200can verify whether a transmission parameter is included after theOM_type field of the corresponding packet. The transmission parametercorresponds to supplemental data required for processing mobile servicedata from the transmitting system and the receiving system.

Herein, the transmission parameter may include data group information,region information within the data group, RS frame information, superframe information, burst information, turbo code information, and RScode information. The burst information may include burst sizeinformation, burst period information, and time information to nextburst. The burst period signifies the period at which the bursttransmitting the same mobile service is repeated. The data groupincludes a plurality of mobile service data packets, and a plurality ofsuch data groups is gathered (or grouped) to form a burst. A burstsection signifies the beginning of a current burst to the beginning of anext burst. Herein, the burst section is classified as a section thatincludes the data group (also referred to as a burst section), and asection that does not include the data group (also referred to as a nonburst section). A burst section is configured of a plurality of fields,wherein one field includes one data group.

The transmission parameter may also include information on how signalsof a symbol domain are encoded in order to transmit the mobile servicedata, and multiplexing information on how the main service data and themobile service data or various types of mobile service data aremultiplexed. The information included in the transmission parameter ismerely exemplary to facilitate the understanding of the presentinvention. And, the adding and deleting of the information included inthe transmission parameter may be easily modified and changed by anyoneskilled in the art. Therefore, the present invention is not limited tothe examples proposed in the description set forth herein. Furthermore,the transmission parameters may be provided from the service multiplexer100 to the transmitter 200. Alternatively, the transmission parametersmay also be set up by an internal controller (not shown) within thetransmitter 200 or received from an external source.

Transmitter

FIG. 3 illustrates a block diagram showing an example of the transmitter200 according to an embodiment of the present invention. Herein, thetransmitter 200 includes a demultiplexer 210, a packet jitter mitigator220, a pre-processor 230, a packet multiplexer 240, a post-processor250, a synchronization (sync) multiplexer 260, and a transmission unit270. Herein, when a data packet is received from the service multiplexer100, the demultiplexer 210 should identify whether the received datapacket corresponds to a main service data packet, a mobile service datapacket, or a null data packet. For example, the demultiplexer 210 usesthe PID within the received data packet so as to identify the mainservice data packet and the mobile service data packet. Then, thedemultiplexer 210 uses a transport_error_indicator field to identify thenull data packet. The main service data packet identified by thedemultiplexer 210 is outputted to the packet jitter mitigator 220, themobile service data packet is outputted to the pre-processor 230, andthe null data packet is discarded. If a transmission parameter isincluded in the null data packet, then the transmission parameter isfirst extracted and outputted to the corresponding block. Thereafter,the null data packet is discarded.

The pre-processor 230 performs an additional encoding process of themobile service data included in the service data packet, which isdemultiplexed and outputted from the demultiplexer 210. Thepre-processor 230 also performs a process of configuring a data group sothat the data group may be positioned at a specific place in accordancewith the purpose of the data, which are to be transmitted on atransmission frame. This is to enable the mobile service data to respondswiftly and strongly against noise and channel changes. Thepre-processor 230 may also refer to the transmission parameter whenperforming the additional encoding process. Also, the pre-processor 230groups a plurality of mobile service data packets to configure a datagroup. Thereafter, known data, mobile service data, RS parity data, andMPEG header are allocated to pre-determined areas within the data group.

Pre-Processor within Transmitter

FIG. 4 illustrates a block diagram showing an example of thepre-processor 230 according to the present invention. The pre-processor230 includes a data randomizer 301, a RS frame encoder 302, a blockprocessor 303, a group formatter 304, a data deinterleaver 305, a packetformatter 306. The data randomizer 301 within the above-describedpre-processor 230 randomizes the mobile service data packet includingthe mobile service data that is inputted through the demultiplexer 210.Then, the data randomizer 301 outputs the randomized mobile service datapacket to the RS frame encoder 302. At this point, since the datarandomizer 301 performs the randomizing process on the mobile servicedata, the randomizing process that is to be performed by the datarandomizer 251 of the post-processor 250 on the mobile service data maybe omitted. The data randomizer 301 may also discard the synchronizationbyte within the mobile service data packet and perform the randomizingprocess. This is an option that may be chosen by the system designer. Inthe example given in the present invention, the randomizing process isperformed without discarding the synchronization byte within the mobileservice data packet.

The RS frame encoder 302 groups a plurality of mobile thesynchronization byte within the mobile service data packets that israndomized and inputted, so as to create a RS frame. Then, the RS frameencoder 302 performs at least one of an error correction encodingprocess and an error detection encoding process in RS frame units.Accordingly, robustness may be provided to the mobile service data,thereby scattering group error that may occur during changes in afrequency environment, thereby enabling the enhanced data to respond tothe frequency environment, which is extremely vulnerable and liable tofrequent changes. Also, the RS frame encoder 302 groups a plurality ofRS frame so as to create a super frame, thereby performing a rowpermutation process in super frame units. The row permutation processmay also be referred to as a row interleaving process. Hereinafter, theprocess will be referred to as row permutation for simplicity.

More specifically, when the RS frame encoder 302 performs the process ofpermuting each row of the super frame in accordance with apre-determined rule, the position of the rows within the super framebefore and after the row permutation process is changed. If the rowpermutation process is performed by super frame units, and even thoughthe section having a plurality of errors occurring therein becomes verylong, and even though the number of errors included in the RS frame,which is to be decoded, exceeds the extent of being able to becorrected, the errors become dispersed within the entire super frame.Thus, the decoding ability is even more enhanced as compared to a singleRS frame.

At this point, as an example of the present invention, RS-encoding isapplied for the error correction encoding process, and a cyclicredundancy check (CRC) encoding is applied for the error detectionprocess. When performing the RS-encoding, parity data that are used forthe error correction are generated. And, when performing the CRCencoding, CRC data that are used for the error detection are generated.The RS encoding is one of forward error correction (FEC) methods. TheFEC corresponds to a technique for compensating errors that occur duringthe transmission process. The CRC data generated by CRC encoding may beused for indicating whether or not the mobile service data have beendamaged by the errors while being transmitted through the channel. Inthe present invention, a variety of error detection coding methods otherthan the CRC encoding method may be used, or the error correction codingmethod may be used to enhance the overall error correction ability ofthe receiving system. Herein, the RS frame encoder 302 refers to apre-determined transmission parameter and/or the transmission parameterprovided from the service multiplexer 100 so as to perform operationsincluding RS frame configuration, RS encoding, CRC encoding, super frameconfiguration, and row permutation in super frame units.

Pre-Processor within RS Frame Encoder

FIG. 5(a) to FIG. 5(e) illustrate error correction encoding and errordetection encoding processed according to an embodiment of the presentinvention. More specifically, the RS frame encoder 302 first divides theinputted mobile service data bytes to units of a predetermined length.The predetermined length is decided by the system designer. And, in theexample of the present invention, the predetermined length is equal to187 bytes, and, therefore, the 187-byte unit will be referred to as apacket for simplicity. For example, when the mobile service data thatare being inputted, as shown in FIG. 5(a), correspond to a MPEGtransport packet stream configured of 188-byte units, the firstsynchronization byte is removed, as shown in FIG. 5(b), so as toconfigure a 187-byte unit. Herein, the synchronization byte is removedbecause each mobile service data packet has the same value.

Herein, the process of removing the synchronization byte may beperformed during a randomizing process of the data randomizer 301 in anearlier process. In this case, the process of the removing thesynchronization byte by the RS frame encoder 302 may be omitted.Moreover, when adding synchronization bytes from the receiving system,the process may be performed by the data derandomizer instead of the RSframe decoder. Therefore, if a removable fixed byte (e.g.,synchronization byte) does not exist within the mobile service datapacket that is being inputted to the RS frame encoder 302, or if themobile service data that are being inputted are not configured in apacket format, the mobile service data that are being inputted aredivided into 187-byte units, thereby configuring a packet for each187-byte unit.

Subsequently, as shown in FIG. 5(c), N number of packets configured of187 bytes is grouped to configure a RS frame. At this point, the RSframe is configured as a RS frame having the size of N(row)*187(column)bytes, in which 187-byte packets are sequentially inputted in a rowdirection. In order to simplify the description of the presentinvention, the RS frame configured as described above will also bereferred to as a first RS frame. More specifically, only pure mobileservice data are included in the first RS frame, which is the same asthe structure configured of 187 N-byte rows. Thereafter, the mobileservice data within the RS frame are divided into an equal size. Then,when the divided mobile service data are transmitted in the same orderas the input order for configuring the RS frame, and when one or moreerrors have occurred at a particular point during thetransmitting/receiving process, the errors are clustered (or gathered)within the RS frame as well. In this case, the receiving system uses aRS erasure decoding method when performing error correction decoding,thereby enhancing the error correction ability. At this point, the Nnumber of columns within the N number of RS frame includes 187 bytes, asshown in FIG. 5(c).

In this case, a (Nc,Kc)−RS encoding process is performed on each column,so as to generate Nc−Kc(=P) number of parity bytes. Then, the newlygenerated P number of parity bytes is added after the very last byte ofthe corresponding column, thereby creating a column of (187+P) bytes.Herein, as shown in FIG. 5(c), Kc is equal to 187 (i.e., Kc=187), and Ncis equal to 187+P (i.e., Nc=187+P). For example, when P is equal to 48,(235,187)−RS encoding process is performed so as to create a column of235 bytes. When such RS encoding process is performed on all N number ofcolumns, as shown in FIG. 5(c), a RS frame having the size ofN(row)*(187+P) (column) bytes may be created, as shown in FIG. 5(d). Inorder to simplify the description of the present invention, the RS framehaving the RS parity inserted therein will be referred to as s second RSframe. More specifically, the second RS frame having the structure of(187+P) rows configured of N bytes may be configured.

As shown in FIG. 5(c) or FIG. 5(d), each row of the RS frame isconfigured of N bytes. However, depending upon channel conditionsbetween the transmitting system and the receiving system, error may beincluded in the RS frame. When errors occur as described above, CRC data(or CRC code or CRC checksum) may be used on each row unit in order toverify whether error exists in each row unit. The RS frame encoder 302may perform CRC encoding on the mobile service data being RS encoded soas to create (or generate) the CRC data. The CRC data being generated byCRC encoding may be used to indicate whether the mobile service datahave been damaged while being transmitted through the channel.

The present invention may also use different error detection encodingmethods other than the CRC encoding method. Alternatively, the presentinvention may use the error correction encoding method to enhance theoverall error correction ability of the receiving system. FIG. 5(e)illustrates an example of using a 2-byte (i.e., 16-bit) CRC checksum asthe CRC data. Herein, a 2-byte CRC checksum is generated for N number ofbytes of each row, thereby adding the 2-byte CRC checksum at the end ofthe N number of bytes. Thus, each row is expanded to (N+2) number ofbytes. Equation 1 below corresponds to an exemplary equation forgenerating a 2-byte CRC checksum for each row being configured of Nnumber of bytes.g(x)=x¹⁶+x¹²+x⁵+1  Equation 1

The process of adding a 2-byte checksum in each row is only exemplary.Therefore, the present invention is not limited only to the exampleproposed in the description set forth herein. In order to simplify theunderstanding of the present invention, the RS frame having the RSparity and CRC checksum added therein will hereinafter be referred to asa third RS frame. More specifically, the third RS frame corresponds to(187+P) number of rows each configured of (N+2) number of bytes. Asdescribed above, when the process of RS encoding and CRC encoding arecompleted, the (N*187)-byte RS frame is expanded to a (N+2)*(187+P)-byteRS frame. Furthermore, the RS frame that is expanded, as shown in FIG.5(e), is inputted to the block processor 303.

As described above, the mobile service data encoded by the RS frameencoder 302 are inputted to the block processor 303. The block processor303 then encodes the inputted mobile service data at a coding rate ofG/H (wherein, G is smaller than H (i.e., G<H)) and then outputted to thegroup formatter 304. More specifically, the block processor 303 dividesthe mobile service data being inputted in byte units into bit units.Then, the G number of bits is encoded to H number of bits. Thereafter,the encoded bits are converted back to byte units and then outputted.For example, if 1 bit of the input data is coded to 2 bits andoutputted, then G is equal to 1 and H is equal to 2 (i.e., G=1 and H=2).Alternatively, if 1 bit of the input data is coded to 4 bits andoutputted, then G is equal to 1 and H is equal to 4 (i.e., G=1 and H=4).Hereinafter, the former coding rate will be referred to as a coding rateof ½ (½-rate coding), and the latter coding rate will be referred to asa coding rate of ¼ (¼-rate coding), for simplicity.

Herein, when using the ¼ coding rate, the coding efficiency is greaterthan when using the ½ coding rate, and may, therefore, provide greaterand enhanced error correction ability. For such reason, when it isassumed that the data encoded at a ¼ coding rate in the group formatter304, which is located near the end portion of the system, are allocatedto an area in which the receiving performance may be deteriorated, andthat the data encoded at a ½ coding rate are allocated to an area havingexcellent receiving performance, the difference in performance may bereduced. At this point, the block processor 303 may also receivesignaling information including transmission parameters. Herein, thesignaling information may also be processed with either ½-rate coding or¼-rate coding as in the step of processing mobile service data.Thereafter, the signaling information is also considered the same as themobile service data and processed accordingly.

Meanwhile, the group formatter inserts mobile service data that areoutputted from the block processor 303 in corresponding areas within adata group, which is configured in accordance with a pre-defined rule.Also, with respect to the data deinterleaving process, each place holderor known data (or known data place holders) are also inserted incorresponding areas within the data group. At this point, the data groupmay be divided into at least one hierarchical area. Herein, the type ofmobile service data being inserted in each area may vary depending uponthe characteristics of each hierarchical area. Additionally, each areamay, for example, be divided based upon the receiving performance withinthe data group. Furthermore, one data group may be configured to includea set of field synchronization data.

In an example given in the present invention, a data group is dividedinto A, B, and C regions in a data configuration prior to datadeinterleaving. At this point, the group formatter 304 allocates themobile service data, which are inputted after being RS encoded and blockencoded, to each of the corresponding regions by referring to thetransmission parameter. FIG. 6A illustrates an alignment of data afterbeing data interleaved and identified, and FIG. 6B illustrates analignment of data before being data interleaved and identified. Morespecifically, a data structure identical to that shown in FIG. 6A istransmitted to a receiving system. Also, the data group configured tohave the same structure as the data structure shown in FIG. 6A isinputted to the data deinterleaver 305.

As described above, FIG. 6A illustrates a data structure prior to datadeinterleaving that is divided into 3 regions, such as region A, regionB, and region C. Also, in the present invention, each of the regions Ato C is further divided into a plurality of regions. Referring to FIG.6A, region A is divided into 5 regions (A1 to A5), region B is dividedinto 2 regions (B1 and B2), and region C is divided into 3 regions (C1to C3). Herein, regions A to C are identified as regions having similarreceiving performances within the data group. Herein, the type of mobileservice data, which are inputted, may also vary depending upon thecharacteristic of each region.

In the example of the present invention, the data structure is dividedinto regions A to C based upon the level of interference of the mainservice data. Herein, the data group is divided into a plurality ofregions to be used for different purposes. More specifically, a regionof the main service data having no interference or a very lowinterference level may be considered to have a more resistant (orstronger) receiving performance as compared to regions having higherinterference levels. Additionally, when using a system inserting andtransmitting known data in the data group, and when consecutively longknown data are to be periodically inserted in the mobile service data,the known data having a predetermined length may be periodicallyinserted in the region having no interference from the main service data(e.g., region A). However, due to interference from the main servicedata, it is difficult to periodically insert known data and also toinsert consecutively long known data to a region having interferencefrom the main service data (e.g., region B and region C).

Hereinafter, examples of allocating data to region A (A1 to A5), regionB (B1 and B2), and region C (C1 to C3) will now be described in detailwith reference to FIG. 6A. The data group size, the number ofhierarchically divided regions within the data group and the size ofeach region, and the number of mobile service data bytes that can beinserted in each hierarchically divided region of FIG. 6A are merelyexamples given to facilitate the understanding of the present invention.Herein, the group formatter 304 creates a data group including places inwhich field synchronization data bytes are to be inserted, so as tocreate the data group that will hereinafter be described in detail.

More specifically, region A is a region within the data group in which along known data sequence may be periodically inserted, and in whichincludes regions wherein the main service data are not mixed (e.g., A1to A5). Also, region A includes a region (e.g., A1) located between afield synchronization region and the region in which the first knowndata sequence is to be inserted. The field synchronization region hasthe length of one segment (i.e., 832 symbols) existing in an ATSCsystem.

For example, referring to FIG. 6A, 2428 bytes of the mobile service datamay be inserted in region A1, 2580 bytes may be inserted in region A2,2772 bytes may be inserted in region A3, 2472 bytes may be inserted inregion A4, and 2772 bytes may be inserted in region A5. Herein, trellisinitialization data or known data, MPEG header, and RS parity are notincluded in the mobile service data. As described above, when region Aincludes a known data sequence at both ends, the receiving system useschannel information that can obtain known data or field synchronizationdata, so as to perform equalization, thereby providing enforcedequalization performance.

Also, region B includes a region located within 8 segments at thebeginning of a field synchronization region within the data group(chronologically placed before region A1) (e.g., region B1), and aregion located within 8 segments behind the very last known datasequence which is inserted in the data group (e.g., region B2). Forexample, 930 bytes of the mobile service data may be inserted in theregion B1, and 1350 bytes may be inserted in region B2. Similarly,trellis initialization data or known data, MPEG header, and RS parityare not included in the mobile service data. In case of region B, thereceiving system may perform equalization by using channel informationobtained from the field synchronization region. Alternatively, thereceiving system may also perform equalization by using channelinformation that may be obtained from the last known data sequence,thereby enabling the system to respond to the channel changes.

Region C includes a region located within 30 segments including andpreceding the 9th segment of the field synchronization region(chronologically located before region A) (e.g., region C1), a regionlocated within 12 segments including and following the 9th segment ofthe very last known data sequence within the data group (chronologicallylocated after region A) (e.g., region C2), and a region located in 32segments after the region C2 (e.g., region C3). For example, 1272 bytesof the mobile service data may be inserted in the region C1, 1560 bytesmay be inserted in region C2, and 1312 bytes may be inserted in regionC3. Similarly, trellis initialization data or known data, MPEG header,and RS parity are not included in the mobile service data. Herein,region C (e.g., region C1) is located chronologically earlier than (orbefore) region A.

Since region C (e.g., region C1) is located further apart from the fieldsynchronization region which corresponds to the closest known dataregion, the receiving system may use the channel information obtainedfrom the field synchronization data when performing channelequalization. Alternatively, the receiving system may also use the mostrecent channel information of a previous data group. Furthermore, inregion C (e.g., region C2 and region C3) located before region A, thereceiving system may use the channel information obtained from the lastknown data sequence to perform equalization. However, when the channelsare subject to fast and frequent changes, the equalization may not beperformed perfectly. Therefore, the equalization performance of region Cmay be deteriorated as compared to that of region B.

When it is assumed that the data group is allocated with a plurality ofhierarchically divided regions, as described above, the block processor303 may encode the mobile service data, which are to be inserted to eachregion based upon the characteristic of each hierarchical region, at adifferent coding rate. For example, the block processor 303 may encodethe mobile service data, which are to be inserted in regions A1 to A5 ofregion A, at a coding rate of ½. Then, the group formatter 304 mayinsert the ½-rate encoded mobile service data to regions A1 to A5.

The block processor 303 may encode the mobile service data, which are tobe inserted in regions B1 and B2 of region B, at a coding rate of ¼having higher error correction ability as compared to the ½-coding rate.Then, the group formatter 304 inserts the ¼-rate coded mobile servicedata in region B1 and region B2. Furthermore, the block processor 303may encode the mobile service data, which are to be inserted in regionsC1 to C3 of region C, at a coding rate of ¼ or a coding rate havinghigher error correction ability than the ¼-coding rate. Then, the groupformatter 304 may either insert the encoded mobile service data toregions C1 to C3, as described above, or leave the data in a reservedregion for future usage.

In addition, the group formatter 304 also inserts supplemental data,such as signaling information that notifies the overall transmissioninformation, other than the mobile service data in the data group. Also,apart from the encoded mobile service data outputted from the blockprocessor 303, the group formatter 304 also inserts MPEG header placeholders, non-systematic RS parity place holders, main service data placeholders, which are related to data deinterleaving in a later process, asshown in FIG. 6A. Herein, the main service data place holders areinserted because the mobile service data bytes and the main service databytes are alternately mixed with one another in regions B and C basedupon the input of the data deinterleaver, as shown in FIG. 6A. Forexample, based upon the data outputted after data deinterleaving, theplace holder for the MPEG header may be allocated at the very beginningof each packet.

Furthermore, the group formatter 304 either inserts known data generatedin accordance with a pre-determined method or inserts known data placeholders for inserting the known data in a later process. Additionally,place holders for initializing the trellis encoding module 256 are alsoinserted in the corresponding regions. For example, the initializationdata place holders may be inserted in the beginning of the known datasequence. Herein, the size of the mobile service data that can beinserted in a data group may vary in accordance with the sizes of thetrellis initialization place holders or known data (or known data placeholders), MPEG header place holders, and RS parity place holders.

The output of the group formatter 304 is inputted to the datadeinterleaver 305. And, the data deinterleaver 305 deinterleaves data byperforming an inverse process of the data interleaver on the data andplace holders within the data group, which are then outputted to thepacket formatter 306. More specifically, when the data and place holderswithin the data group configured, as shown in FIG. 6A, are deinterleavedby the data deinterleaver 305, the data group being outputted to thepacket formatter 306 is configured to have the structure shown in FIG.6B.

The packet formatter 306 removes the main service data place holders andthe RS parity place holders that were allocated for the deinterleavingprocess from the deinterleaved data being inputted. Then, the packetformatter 306 groups the remaining portion and replaces the 4-byte MPEGheader place holder with an MPEG header having a null packet PID (or anunused PID from the main service data packet). Also, when the groupformatter 304 inserts known data place holders, the packet formatter 306may insert actual known data in the known data place holders, or maydirectly output the known data place holders without any modification inorder to make replacement insertion in a later process. Thereafter, thepacket formatter 306 identifies the data within the packet-formatteddata group, as described above, as a 188-byte unit mobile service datapacket (i.e., MPEG TS packet), which is then provided to the packetmultiplexer 240.

The packet multiplexer 240 multiplexes the mobile service data packetoutputted from the pre-processor 230 and the main service data packetoutputted from the packet jitter mitigator 220 in accordance with apre-defined multiplexing method. Then, the packet multiplexer 240outputs the multiplexed data packets to the data randomizer 251 of thepost-processor 250. Herein, the multiplexing method may vary inaccordance with various variables of the system design. One of themultiplexing methods of the packet formatter 240 consists of providing aburst section along a time axis, and, then, transmitting a plurality ofdata groups during a burst section within the burst section, andtransmitting only the main service data during the non burst sectionwithin the burst section. Herein, the burst section indicates thesection starting from the beginning of the current burst until thebeginning of the next burst.

At this point, the main service data may be transmitted during the burstsection. The packet multiplexer 240 refers to the transmissionparameter, such as information on the burst size or the burst period, soas to be informed of the number of data groups and the period of thedata groups included in a single burst. Herein, the mobile service dataand the main service data may co-exist in the burst section, and onlythe main service data may exist in the non burst section. Therefore, amain data service section transmitting the main service data may existin both burst and non burst sections. At this point, the main dataservice section within the burst section and the number of main dataservice packets included in the non burst section may either bedifferent from one another or be the same.

When the mobile service data are transmitted in a burst structure, inthe receiving system receiving only the mobile service data turns thepower on only during the burst section, thereby receiving thecorresponding data. Alternatively, in the section transmitting only themain service data, the power is turned off so that the main service dataare not received in this section. Thus, the power consumption of thereceiving system may be reduced.

Detailed Embodiments of the RS Frame Structure and Packet Multiplexing

Hereinafter, detailed embodiments of the pre-processor 230 and thepacket multiplexer 240 will now be described. According to an embodimentof the present invention, the N value corresponding to the length of arow, which is included in the RS frame that is configured by the RSframe encoder 302, is set to 538. Accordingly, the RS frame encoder 302receives 538 transport stream (TS) packets so as to configure a first RSframe having the size of 538*187 bytes. Thereafter, as described above,the first RS frame is processed with a (235,187)−RS encoding process soas to configure a second RS frame having the size of 538*235 bytes.Finally, the second RS frame is processed with generating a 16-bitchecksum so as to configure a third RS frame having the sizes of540*235.

Meanwhile, as shown in FIG. 6A, the sum of the number of bytes ofregions A1 to A5 of region A, in which ½-rate encoded mobile servicedata are to be inserted, among the plurality of regions within the datagroup is equal to 13024 bytes (=2428+2580+2772+2472+2772 bytes). Herein,the number of byte prior to performing the ½-rate encoding process isequal to 6512 (=13024/2). On the other hand, the sum of the number ofbytes of regions B1 and B2 of region B, in which ¼-rate encoded mobileservice data are to be inserted, among the plurality of regions withinthe data group is equal to 2280 bytes (=930+1350 bytes). Herein, thenumber of byte prior to performing the ¼-rate encoding process is equalto 570 (=2280/4).

In other words, when 7082 bytes of mobile service data are inputted tothe block processor 303, 6512 byte are expanded to 13024 bytes by being½-rate encoded, and 570 bytes are expanded to 2280 bytes by being ¼-rateencoded. Thereafter, the block processor 303 inserts the mobile servicedata expanded to 13024 bytes in regions A1 to A5 of region A and, also,inserts the mobile service data expanded to 2280 bytes in regions B1 andB2 of region B. Herein, the 7082 bytes of mobile service data beinginputted to the block processor 303 may be divided into an output of theRS frame encoder 302 and signaling information. In the presentinvention, among the 7082 bytes of mobile service data, 7050 bytescorrespond to the output of the RS frame encoder 302, and the remaining32 bytes correspond to the signaling information data. Then, ½-rateencoding or ¼-rate encoding is performed on the corresponding databytes.

Meanwhile, a RS frame being processed with RS encoding and CRC encodingfrom the RS frame encoder 302 is configured of 540*235 bytes, in otherwords, 126900 bytes. The 126900 bytes are divided by 7050-byte unitsalong the time axis, so as to produce 7050-byte units. Thereafter, a32-byte unit of signaling information data is added to the 7050-byteunit mobile service data being outputted from the RS frame encoder 302.Subsequently, the RS frame encoder 302 performs ½-rate encoding or¼-rate encoding on the corresponding data bytes, which are thenoutputted to the group formatter 304. Accordingly, the group formatter304 inserts the ½-rate encoded data in region A and the ¼-rate encodeddata in region B.

The process of deciding an N value that is required for configuring theRS frame from the RS frame encoder 302 will now be described in detail.More specifically, the size of the final RS frame (i.e., the third RSframe), which is RS encoded and CRC encoded from the RS frame encoder302, which corresponds to (N+2)*235 bytes should be allocated to Xnumber of groups, wherein X is an integer. Herein, in a single datagroup, 7050 data bytes prior to being encoded are allocated. Therefore,if the (N+2)*235 bytes are set to be the exact multiple of7050(=30*235), the output data of the RS frame encoder 302 may beefficiently allocated to the data group. According to an embodiment ofthe present invention, the value of N is decided so that (N+2) becomes amultiple of 30. For example, in the present invention, N is equal to538, and (N+2)(=540) divided by 30 is equal to 18. This indicates thatthe mobile service data within one RS frame are processed with either½-rate encoding or ¼-rate encoding. The encoded mobile service data arethen allocated to 18 data groups.

FIG. 7 illustrates a process of dividing the RS frame according to thepresent invention. More specifically, the RS frame having the size of(N+2)*235 is divided into 30*235 byte blocks. Then, the divided blocksare mapped to a single group. In other words, the data of a block havingthe size of 30*235 bytes are processed with one of a ½-rate encodingprocess and a ¼-rate encoding process and are, then, inserted in a datagroup. Thereafter, the data group having corresponding data and placeholders inserted in each hierarchical region divided by the groupformatter 304 passes through the data deinterleaver 305 and the packetformatter 306 so as to be inputted to the packet multiplexer 240.

FIG. 8 illustrates exemplary operations of a packet multiplexer fortransmitting the data group according to the present invention. Morespecifically, the packet multiplexer 240 multiplexes a field including adata group, in which the mobile service data and main service data aremixed with one another, and a field including only the main servicedata. Thereafter, the packet multiplexer 240 outputs the multiplexedfields to the data randomizer 251. At this point, in order to transmitthe RS frame having the size of 540*235 bytes, 18 data groups should betransmitted. Herein, each data group includes field synchronizationdata, as shown in FIG. 6A. Therefore, the 18 data groups are transmittedduring 18 field sections, and the section during which the 18 datagroups are being transmitted corresponds to the burst section.

In each field within the burst section, a data group including fieldsynchronization data is multiplexed with main service data, which arethen outputted. For example, in the embodiment of the present invention,in each field within the burst section, a data group having the size of118 segments is multiplexed with a set of main service data having thesize of 194 segments. Referring to FIG. 8, during the burst section(i.e., during the 18 field sections), a field including 18 data groupsis transmitted. Then, during the non burst section that follows (i.e.,during the 12 field sections), a field consisting only of the mainservice data is transmitted. Subsequently, during a subsequent burstsection, 18 fields including 18 data groups are transmitted. And, duringthe following non burst section, 12 fields consisting only of the mainservice data are transmitted.

Furthermore, in the present invention, the same type of data service maybe provided in the first burst section including the first 18 datagroups and in the second burst section including the next 18 datagroups. Alternatively, different types of data service may be providedin each burst section. For example, when it is assumed that differentdata service types are provided to each of the first burst section andthe second burst section, and that the receiving system wishes toreceive only one type of data service, the receiving system turns thepower on only during the corresponding burst section including thedesired data service type so as to receive the corresponding 18 datafields. Then, the receiving system turns the power off during theremaining 42 field sections so as to prevent other data service typesfrom being received. Thus, the amount of power consumption of thereceiving system may be reduced. In addition, the receiving systemaccording to the present invention is advantageous in that one RS framemay be configured from the 18 data groups that are received during asingle burst section.

According to the present invention, the number of data groups includedin a burst section may vary based upon the size of the RS frame, and thesize of the RS frame varies in accordance with the value N. Morespecifically, by adjusting the value N, the number of data groups withinthe burst section may be adjusted. Herein, in an example of the presentinvention, the (235,187)−RS encoding process adjusts the value N duringa fixed state. Furthermore, the size of the mobile service data that canbe inserted in the data group may vary based upon the sizes of thetrellis initialization data or known data, the MPEG header, and the RSparity, which are inserted in the corresponding data group.

Meanwhile, since a data group including mobile service data in-betweenthe data bytes of the main service data during the packet multiplexingprocess, the shifting of the chronological position (or place) of themain service data packet becomes relative. Also, a system object decoder(i.e., MPEG decoder) for processing the main service data of thereceiving system, receives and decodes only the main service data andrecognizes the mobile service data packet as a null data packet.Therefore, when the system object decoder of the receiving systemreceives a main service data packet that is multiplexed with the datagroup, a packet jitter occurs.

At this point, since a multiple-level buffer for the video data existsin the system object decoder and the size of the buffer is relativelylarge, the packet jitter generated from the packet multiplexer 240 doesnot cause any serious problem in case of the video data. However, sincethe size of the buffer for the audio data is relatively small, thepacket jitter may cause considerable problem. More specifically, due tothe packet jitter, an overflow or underflow may occur in the buffer forthe main service data of the receiving system (e.g., the buffer for theaudio data). Therefore, the packet jitter mitigator 220 re-adjusts therelative position of the main service data packet so that the overflowor underflow does not occur in the system object decoder.

In the present invention, examples of repositioning places for the audiodata packets within the main service data in order to minimize theinfluence on the operations of the audio buffer will be described indetail. The packet jitter mitigator 220 repositions the audio datapackets in the main service data section so that the audio data packetsof the main service data can be as equally and uniformly aligned andpositioned as possible. The standard for repositioning the audio datapackets in the main service data performed by the packet jittermitigator 220 will now be described. Herein, it is assumed that thepacket jitter mitigator 220 knows the same multiplexing information asthat of the packet multiplexer 240, which is placed further behind thepacket jitter mitigator 220.

Firstly, if one audio data packet exists in the main service datasection (e.g., the main service data section positioned between two datagroups) within the burst section, the audio data packet is positioned atthe very beginning of the main service data section. Alternatively, iftwo audio data packets exist in the corresponding data section, oneaudio data packet is positioned at the very beginning and the otheraudio data packet is positioned at the very end of the main service datasection. Further, if more than three audio data packets exist, one audiodata packet is positioned at the very beginning of the main service datasection, another is positioned at the very end of the main service datasection, and the remaining audio data packets are equally positionedbetween the first and last audio data packets. Secondly, during the mainservice data section placed immediately before the beginning of a burstsection (i.e., during a non burst section), the audio data packet isplaced at the very end of the corresponding section.

Thirdly, during a main service data section within the non burst sectionafter the burst section, the audio data packet is positioned at the veryend of the main service data section. Finally, the data packets otherthan audio data packets are positioned in accordance with the inputtedorder in vacant spaces (i.e., spaces that are not designated for theaudio data packets). Meanwhile, when the positions of the main servicedata packets are relatively re-adjusted, associated program clockreference (PCR) values may also be modified accordingly. The PCR valuecorresponds to a time reference value for synchronizing the time of theMPEG decoder. Herein, the PCR value is inserted in a specific region ofa TS packet and then transmitted.

In the example of the present invention, the packet jitter mitigator 220also performs the operation of modifying the PCR value. The output ofthe packet jitter mitigator 220 is inputted to the packet multiplexer240. As described above, the packet multiplexer 240 multiplexes the mainservice data packet outputted from the packet jitter mitigator 220 withthe mobile service data packet outputted from the pre-processor 230 intoa burst structure in accordance with a pre-determined multiplexing rule.Then, the packet multiplexer 240 outputs the multiplexed data packets tothe data randomizer 251 of the post-processor 250.

If the inputted data correspond to the main service data packet, thedata randomizer 251 performs the same randomizing process as that of theconventional randomizer. More specifically, the synchronization bytewithin the main service data packet is deleted. Then, the remaining 187data bytes are randomized by using a pseudo random byte generated fromthe data randomizer 251. Thereafter, the randomized data are outputtedto the RS encoder/non-systematic RS encoder 252.

On the other hand, if the inputted data correspond to the mobile servicedata packet, the data randomizer 251 may randomize only a portion of thedata packet. For example, if it is assumed that a randomizing processhas already been performed in advance on the mobile service data packetby the pre-processor 230, the data randomizer 251 deletes thesynchronization byte from the 4-byte MPEG header included in the mobileservice data packet and, then, performs the randomizing process only onthe remaining 3 data bytes of the MPEG header. Thereafter, therandomized data bytes are outputted to the RS encoder/non-systematic RSencoder 252. More specifically, the randomizing process is not performedon the remaining portion of the mobile service data excluding the MPEGheader. In other words, the remaining portion of the mobile service datapacket is directly outputted to the RS encoder/non-systematic RS encoder252 without being randomized. Also, the data randomizer 251 may or maynot perform a randomizing process on the known data (or known data placeholders) and the initialization data place holders included in themobile service data packet.

The RS encoder/non-systematic RS encoder 252 performs an RS encodingprocess on the data being randomized by the data randomizer 251 or onthe data bypassing the data randomizer 251, so as to add 20 bytes of RSparity data. Thereafter, the processed data are outputted to the datainterleaver 253. Herein, if the inputted data correspond to the mainservice data packet, the RS encoder/non-systematic RS encoder 252performs the same systematic RS encoding process as that of theconventional broadcasting system, thereby adding the 20-byte RS paritydata at the end of the 187-byte data. Alternatively, if the inputteddata correspond to the mobile service data packet, the RSencoder/non-systematic RS encoder 252 performs a non-systematic RSencoding process. At this point, the 20-byte RS parity data obtainedfrom the non-systematic RS encoding process are inserted in apre-decided parity byte place within the mobile service data packet.

The data interleaver 253 corresponds to a byte unit convolutionalinterleaver. The output of the data interleaver 253 is inputted to theparity replacer 254 and to the non-systematic RS encoder 255. Meanwhile,a process of initializing a memory within the trellis encoding module256 is primarily required in order to decide the output data of thetrellis encoding module 256, which is located after the parity replacer254, as the known data pre-defined according to an agreement between thereceiving system and the transmitting system. More specifically, thememory of the trellis encoding module 256 should first be initializedbefore the received known data sequence is trellis-encoded. At thispoint, the beginning portion of the known data sequence that is receivedcorresponds to the initialization data place holder and not to theactual known data. Herein, the initialization data place holder has beenincluded in the data by the group formatter within the pre-processor 230in an earlier process. Therefore, the process of generatinginitialization data and replacing the initialization data place holderof the corresponding memory with the generated initialization data arerequired to be performed immediately before the inputted known datasequence is trellis-encoded.

Additionally, a value of the trellis memory initialization data isdecided and generated based upon a memory status of the trellis encodingmodule 256. Further, due to the newly replaced initialization data, aprocess of newly calculating the RS parity and replacing the RS parity,which is outputted from the data interleaver 253, with the newlycalculated RS parity is required. Therefore, the non-systematic RSencoder 255 receives the mobile service data packet including theinitialization data place holders, which are to be replaced with theactual initialization data, from the data interleaver 253 and alsoreceives the initialization data from the trellis encoding module 256.

Among the inputted mobile service data packet, the initialization dataplace holders are replaced with the initialization data, and the RSparity data that are added to the mobile service data packet are removedand processed with non-systematic RS encoding. Thereafter, the new RSparity obtained by performing the non-systematic RS encoding process isoutputted to the parity replacer 255. Accordingly, the parity replacer255 selects the output of the data interleaver 253 as the data withinthe mobile service data packet, and the parity replacer 255 selects theoutput of the non-systematic RS encoder 255 as the RS parity. Theselected data are then outputted to the trellis encoding module 256.

Meanwhile, if the main service data packet is inputted or if the mobileservice data packet, which does not include any initialization dataplace holders that are to be replaced, is inputted, the parity replacer254 selects the data and RS parity that are outputted from the datainterleaver 253. Then, the parity replacer 254 directly outputs theselected data to the trellis encoding module 256 without anymodification. The trellis encoding module 256 converts the byte-unitdata to symbol units and performs a 12-way interleaving process so as totrellis-encode the received data. Thereafter, the processed data areoutputted to the synchronization multiplexer 260.

The synchronization multiplexer 260 inserts a field synchronizationsignal and a segment synchronization signal to the data outputted fromthe trellis encoding module 256 and, then, outputs the processed data tothe pilot inserter 271 of the transmission unit 270. Herein, the datahaving a pilot inserted therein by the pilot inserter 271 are modulatedby the modulator 272 in accordance with a pre-determined modulatingmethod (e.g., a VSB method). Thereafter, the modulated data aretransmitted to each receiving system though the radio frequency (RF)up-converter 273.

Block Processor

FIG. 9 illustrates a block diagram showing a structure of a blockprocessor according to the present invention. Herein, the blockprocessor includes a byte-bit converter 401, a symbol encoder 402, asymbol interleaver 403, and a symbol-byte converter 404. The byte-bitconverter 401 divides the mobile service data bytes that are inputtedfrom the RS frame encoder 112 into bits, which are then outputted to thesymbol encoder 402. The byte-bit converter 401 may also receivesignaling information including transmission parameters. The signalinginformation data bytes are also divided into bits so as to be outputtedto the symbol encoder 402. Herein, the signaling information includingtransmission parameters may be processed with the same data processingstep as that of the mobile service data. More specifically, thesignaling information may be inputted to the block processor 303 bypassing through the data randomizer 301 and the RS frame encoder 302.Alternatively, the signaling information may also be directly outputtedto the block processor 303 without passing though the data randomizer301 and the RS frame encoder 302.

The symbol encoder 402 corresponds to a G/H-rate encoder encoding theinputted data from G bits to H bits and outputting the data encoded atthe coding rate of G/H. According to the embodiment of the presentinvention, it is assumed that the symbol encoder 402 performs either acoding rate of ½ (also referred to as a ½-rate encoding process) or anencoding process at a coding rate of ¼ (also referred to as a ¼-rateencoding process). The symbol encoder 402 performs one of ½-rateencoding and ¼-rate encoding on the inputted mobile service data andsignaling information. Thereafter, the signaling information is alsorecognized as the mobile service data and processed accordingly.

In case of performing the ½-rate coding process, the symbol encoder 402receives 1 bit and encodes the received 1 bit to 2 bits (i.e., 1symbol). Then, the symbol encoder 402 outputs the processed 2 bits (or 1symbol). On the other hand, in case of performing the ¼-rate encodingprocess, the symbol encoder 402 receives 1 bit and encodes the received1 bit to 4 bits (i.e., 2 symbols). Then, the symbol encoder 402 outputsthe processed 4 bits (or 2 symbols).

FIG. 10 illustrates a detailed block diagram of the symbol encoder 402shown in FIG. 9. The symbol encoder 402 includes two delay units 501 and503 and three adders 502, 504, and 505. Herein, the symbol encoder 402encodes an input data bit U and outputs the coded bit U to 4 bits (u0 tou4). At this point, the data bit U is directly outputted as uppermostbit u0 and simultaneously encoded as lower bit u1u2u3 and thenoutputted. More specifically, the input data bit U is directly outputtedas the uppermost bit u0 and simultaneously outputted to the first andthird adders 502 and 505. The first adder 502 adds the input data bit Uand the output bit of the first delay unit 501 and, then, outputs theadded bit to the second delay unit 503. Then, the data bit delayed by apredetermined time (e.g., by 1 clock) in the second delay unit 503 isoutputted as lower bit u1 and simultaneously fed-back to the first delayunit 501. The first delay unit 501 delays the data bit fed-back from thesecond delay unit 503 by a pre-determined time (e.g., by 1 clock). Then,the first delay unit 501 outputs the delayed data bit to the first adder502 and the second adder 504. The second adder 504 adds the data bitsoutputted from the first and second delay units 501 and 503 as a lowerbit u2. The third adder 505 adds the input data bit U and the output ofthe second delay unit 503 and outputs the added data bit as a lower bitu3.

At this point, if the input data bit U corresponds to data encoded at a½-coding rate, the symbol encoder 402 configures a symbol with u1u0 bitsfrom the 4 output bits u0u1u2u3. Then, the symbol encoder 402 outputsthe newly configured symbol. Alternatively, if the input data bit Ucorresponds to data encoded at a ¼-coding rate, the symbol encoder 402configures and outputs a symbol with bits u1u0 and, then, configures andoutputs another symbol with bits u2u3. According to another embodimentof the present invention, if the input data bit U corresponds to dataencoded at a ¼-coding rate, the symbol encoder 402 may also configureand output a symbol with bits u1u0, and then repeat the process onceagain and output the corresponding bits. According to yet anotherembodiment of the present invention, the symbol encoder outputs all fouroutput bits U u0u1u2u3. Then, when using the ½-coding rate, the symbolinterleaver 403 located behind the symbol encoder 402 selects only thesymbol configured of bits u1u0 from the four output bits u0u1u2u3.Alternatively, when using the ¼-coding rate, the symbol interleaver 403may select the symbol configured of bits u1u0 and then select anothersymbol configured of bits u2u3. According to another embodiment, whenusing the ¼-coding rate, the symbol interleaver 403 may repeatedlyselect the symbol configured of bits u1u0.

The output of the symbol encoder 402 is inputted to the symbolinterleaver 403. Then, the symbol interleaver 403 performs blockinterleaving in symbol units on the data outputted from the symbolencoder 402. Any interleaver performing structural rearrangement (orrealignment) may be applied as the symbol interleaver 403 of the blockprocessor. However, in the present invention, a variable length symbolinterleaver that can be applied even when a plurality of lengths isprovided for the symbol, so that its order may be rearranged, may alsobe used.

FIG. 11 illustrates a symbol interleaver according to an embodiment ofthe present invention. Herein, the symbol interleaver according to theembodiment of the present invention corresponds to a variable lengthsymbol interleaver that may be applied even when a plurality of lengthsis provided for the symbol, so that its order may be rearranged.Particularly, FIG. 11 illustrates an example of the symbol interleaverwhen K=6 and L=8. Herein, K indicates a number of symbols that areoutputted for symbol interleaving from the symbol encoder 402. And, Lrepresents a number of symbols that are actually interleaved by thesymbol interleaver 403.

In the present invention, the symbol intereleaver 403 should satisfy theconditions of (wherein n is an integer) and of. If there is a differencein value between K and L, (L−K) number of null (or dummy) symbols isadded, thereby creating an interleaving pattern. Therefore, K becomes ablock size of the actual symbols that are inputted to the symbolinterleaver 403 in order to be interleaved. L becomes an interleavingunit when the interleaving process is performed by an interleavingpattern created from the symbol interleaver 403. The example of what isdescribed above is illustrated in FIG. 11.

More specifically, FIG. 11(a) to FIG. 11(c) illustrate a variable lengthinterleaving process of a symbol interleaver shown in FIG. 9. The numberof symbols outputted from the symbol encoder 402 in order to beinterleaved is equal to 6 (i.e., K=6). In other words, 6 symbols areoutputted from the symbol encoder 402 in order to be interleaved. And,the actual interleaving unit (L) is equal to 8 symbols. Therefore, asshown in FIG. 11(a), 2 symbols are added to the null (or dummy) symbol,thereby creating the interleaving pattern. Equation 2 shown belowdescribed the process of sequentially receiving K number of symbols, theorder of which is to be rearranged, and obtaining an L value satisfyingthe conditions of (wherein n is an integer) and of, thereby creating theinterleaving so as to realign (or rearrange) the symbol order.In relation to all places, wherein 0≦i≦L−1,P(i)={S×i×(i+1)/2}mod L  Equation 2

Herein, L≧K, L=2″, and n and S are integers. Referring to FIG. 11, it isassumed that S is equal to 89, and that L is equal to 8, and FIG. 11illustrates the created interleaving pattern and an example of theinterleaving process. As shown in FIG. 11(b), the order of K number ofinput symbols and (L−K) number of null symbols is rearranged by usingthe above-mentioned Equation 2. Then, as shown in FIG. 11(c), the nullbyte places are removed, so as to rearrange the order, by using Equation3 shown below. Thereafter, the symbol that is interleaved by therearranged order is then outputted to the symbol-byte converter.if P(i)>K−1, then P(i) place is removed and rearranged  Equation 3

Subsequently, the symbol-byte converter 404 converts to bytes the mobileservice data symbols, having the rearranging of the symbol ordercompleted and then outputted in accordance with the rearranged order,and thereafter outputs the converted bytes to the group formatter 304.

FIG. 12A illustrates a block diagram showing the structure of a blockprocessor according to another embodiment of the present invention.Herein, the block processor includes an interleaving unit 610 and ablock formatter 620. The interleaving unit 610 may include a byte-symbolconverter 611, a symbol-byte converter 612, a symbol interleaver 613,and a symbol-byte converter 614. Herein, the symbol interleaver 613 mayalso be referred to as a block interleaver.

The byte-symbol converter 611 of the interleaving unit 610 converts themobile service data X outputted in byte units from the RS frame encoder302 to symbol units. Then, the byte-symbol converter 611 outputs theconverted mobile service data symbols to the symbol-byte converter 612and the symbol interleaver 613. More specifically, the byte-symbolconverter 611 converts each 2 bits of the inputted mobile service databyte (=8 bits) to 1 symbol and outputs the converted symbols. This isbecause the input data of the trellis encoding module 256 consist ofsymbol units configured of 2 bits. The relationship between the blockprocessor 303 and the trellis encoding module 256 will be described indetail in a later process. At this point, the byte-symbol converter 611may also receive signaling information including transmissionparameters. Furthermore, the signaling information bytes may also bedivided into symbol units and then outputted to the symbol-byteconverter 612 and the symbol interleaver 613.

The symbol-byte converter 612 groups 4 symbols outputted from thebyte-symbol converter 611 so as to configure a byte. Thereafter, theconverted data bytes are outputted to the block formatter 620. Herein,each of the symbol-byte converter 612 and the byte-symbol converter 611respectively performs an inverse process on one another. Therefore, theyield of these two blocks is offset. Accordingly, as shown in FIG. 12B,the input data X bypass the byte-symbol converter 611 and thesymbol-byte converter 612 and are directly inputted to the blockformatter 620. More specifically, the interleaving unit 610 of FIG. 12Bhas a structure equivalent to that of the interleaving unit shown inFIG. 12A. Therefore, the same reference numerals will be used in FIG.12A and FIG. 12B.

The symbol interleaver 613 performs block interleaving in symbol unitson the data that are outputted from the byte-symbol converter 611.Subsequently, the symbol interleaver 613 outputs the interleaved data tothe symbol-byte converter 614. Herein, any type of interleaver that canrearrange the structural order may be used as the symbol interleaver 613of the present invention. In the example given in the present invention,a variable length interleaver that may be applied for symbols having awide range of lengths, the order of which is to be rearranged. Forexample, the symbol interleaver of FIG. 11 may also be used in the blockprocessor shown in FIG. 12A and FIG. 12B.

The symbol-byte converter 614 outputs the symbols having the rearrangingof the symbol order completed, in accordance with the rearranged order.Thereafter, the symbols are grouped to be configured in byte units,which are then outputted to the block formatter 620. More specifically,the symbol-byte converter 614 groups 4 symbols outputted from the symbolinterleaver 613 so as to configure a data byte. As shown in FIG. 13, theblock formatter 620 performs the process of aligning the output of eachsymbol-byte converter 612 and 614 within the block in accordance with aset standard. Herein, the block formatter 620 operates in associationwith the trellis encoding module 256.

More specifically, the block formatter 620 decides the output order ofthe mobile service data outputted from each symbol-byte converter 612and 614 while taking into consideration the place (or order) of the dataexcluding the mobile service data that are being inputted, wherein themobile service data include main service data, known data, RS paritydata, and MPEG header data.

According to the embodiment of the present invention, the trellisencoding module 256 is provided with 12 trellis encoders. FIG. 14illustrates a block diagram showing the trellis encoding module 256according to the present invention. In the example shown in FIG. 14, 12identical trellis encoders are combined to the interleaver in order todisperse noise. Herein, each trellis encoder may be provided with apre-coder.

FIG. 15A illustrates the block processor 303 being concatenated with thetrellis encoding module 256. In the transmitting system, a plurality ofblocks actually exists between the pre-processor 230 including the blockprocessor 303 and the trellis encoding module 256, as shown in FIG. 3.Conversely, the receiving system considers the pre-processor 230 to beconcatenated with the trellis encoding module 256, thereby performingthe decoding process accordingly. However, the data excluding the mobileservice data that are being inputted to the trellis encoding module 256,wherein the mobile service data include main service data, known data,RS parity data, and MPEG header data, correspond to data that are addedto the blocks existing between the block processor 303 and the trellisencoding module 256. FIG. 15B illustrates an example of a data processor650 being positioned between the block processor 303 and the trellisencoding module 256, while taking the above-described instance intoconsideration.

Herein, when the interleaving unit 610 of the block processor 303performs a ½-rate encoding process, the interleaving unit 610 may beconfigured as shown in FIG. 12A (or FIG. 12B). Referring to FIG. 3, forexample, the data processor 650 may include a group formatter 304, adata deinterleaver 305, a packet formatter 306, a packet multiplexer240, and a post-processor 250, wherein the post-processor 250 includes adata randomizer 251, a RS encoder/non-systematic RS encoder 252, a datainterleaver 253, a parity replacer 254, and a non-systematic RS encoder255.

At this point, the trellis encoding module 256 symbolizes the data thatare being inputted so as to divide the symbolized data and to send thedivided data to each trellis encoder in accordance with a pre-definedmethod. Herein, one byte is converted into 4 symbols, each beingconfigured of 2 bits. Also, the symbols created from the single databyte are all transmitted to the same trellis encoder. Accordingly, eachtrellis encoder pre-codes an upper bit of the input symbol, which isthen outputted as the uppermost output bit C2. Alternatively, eachtrellis encoder trellis-encodes a lower bit of the input symbol, whichis then outputted as two output bits C1 and C0. The block formatter 620is controlled so that the data byte outputted from each symbol-byteconverter can be transmitted to different trellis encoders.

Hereinafter, the operation of the block formatter 620 will now bedescribed in detail with reference to FIG. 9 to FIG. 12. Referring toFIG. 12A, for example, the data byte outputted from the symbol-byteconverter 612 and the data byte outputted from the symbol-byte converter614 are inputted to different trellis encoders of the trellis encodingmodule 256 in accordance with the control of the block formatter 620.Hereinafter, the data byte outputted from the symbol-byte converter 612will be referred to as X, and the data byte outputted from thesymbol-byte converter 614 will be referred to as Y, for simplicity.Referring to FIG. 13(a), each number (i.e., 0 to 11) indicates the firstto twelfth trellis encoders of the trellis encoding module 256,respectively.

In addition, the output order of both symbol-byte converters arearranged (or aligned) so that the data bytes outputted from thesymbol-byte converter 612 are respectively inputted to the 0th to 5thtrellis encoders (0 to 5) of the trellis encoding module 256, and thatthe data bytes outputted from the symbol-byte converter 614 arerespectively inputted to the 6th to 11th trellis encoders (6 to 11) ofthe trellis encoding module 256. Herein, the trellis encoders having thedata bytes outputted from the symbol-byte converter 612 allocatedtherein, and the trellis encoders having the data bytes outputted fromthe symbol-byte converter 614 allocated therein are merely examplesgiven to simplify the understanding of the present invention.Furthermore, according to an embodiment of the present invention, andassuming that the input data of the block processor 303 correspond to ablock configured of 12 bytes, the symbol-byte converter 612 outputs 12data bytes from X0 to X11, and the symbol-byte converter 614 outputs 12data bytes from Y0 to Y11.

FIG. 13(b) illustrates an example of data being inputted to the trellisencoding module 256. Particularly, FIG. 13(b) illustrates an example ofnot only the mobile service data but also the main service data and RSparity data being inputted to the trellis encoding module 256, so as tobe distributed to each trellis encoder. More specifically, the mobileservice data outputted from the block processor 303 pass through thegroup formatter 304, from which the mobile service data are mixed withthe main service data and RS parity data and then outputted, as shown inFIG. 13(a). Accordingly, each data byte is respectively inputted to the12 trellis encoders in accordance with the positions (or places) withinthe data group after being data-interleaved.

Herein, when the output data bytes X and Y of the symbol-byte converters612 and 614 are allocated to each respective trellis encoder, the inputof each trellis encoder may be configured as shown in FIG. 13(b). Morespecifically, referring to FIG. 13(b), the six mobile service data bytes(X0 to X5) outputted from the symbol-byte converter 612 are sequentiallyallocated (or distributed) to the first to sixth trellis encoders (0 to5) of the trellis encoding module 256. Also, the 2 mobile service databytes Y0 and Y1 outputted from the symbol-byte converter 614 aresequentially allocated to the 7th and 8th trellis encoders (6 and 7) ofthe trellis encoding module 256. Thereafter, among the 5 main servicedata bytes, 4 data bytes are sequentially allocated to the 9th and 12thtrellis encoders (8 to 11) of the trellis encoding module 256. Finally,the remaining 1 byte of the main service data byte is allocated onceagain to the first trellis encoder (0).

It is assumed that the mobile service data, the main service data, andthe RS parity data are allocated to each trellis encoder, as shown inFIG. 13(b). It is also assumed that, as described above, the input ofthe block processor 303 is configured of 12 bytes, and that 12 bytesfrom X0 to X11 are outputted from the symbol-byte converter 612, andthat 12 bytes from Y0 to Y11 are outputted from the symbol-byteconverter 614. In this case, as shown in FIG. 13(c), the block formatter620 arranges the data bytes that are to be outputted from thesymbol-byte converters 612 and 614 by the order of X0 to X5, Y0, Y1, X6to X10, Y2 to Y7, X11, and Y8 to Y11. More specifically, the trellisencoder that is to perform the encoding process is decided based uponthe position (or place) within the transmission frame in which each databyte is inserted. At this point, not only the mobile service data butalso the main service data, the MPEG header data, and the RS parity dataare also inputted to the trellis encoding module 256. Herein, it isassumed that, in order to perform the above-described operation, theblock formatter 620 is informed of (or knows) the information on thedata group format after the data-interleaving process.

FIG. 16 illustrates a block diagram of the block processor performing anencoding process at a coding rate of 1/N according to an embodiment ofthe present invention. Herein, the block processor includes (N−1) numberof symbol interleavers 741 to 74N−1, which are configured in a parallelstructure. More specifically, the block processor having the coding rateof 1/N consists of a total of N number of branches (or paths) includinga branch (or path), which is directly transmitted to the block formatter730. In addition, the symbol interleaver 741 to 74N−1 of each branch mayeach be configured of a different symbol interleaver. Furthermore, (N−1)number of symbol-byte converter 751 to 75N−1 each corresponding to each(N−1) number of symbol interleavers 741 to 74N−1 may be included at theend of each symbol interleaver, respectively. Herein, the output data ofthe (N−1) number of symbol-byte converter 751 to 75N−1 are also inputtedto the block formatter 730.

In the example of the present invention, N is equal to or smaller than12. If N is equal to 12, the block formatter 730 may align the outputdata so that the output byte of the 12th symbol-byte converter 75N−1 isinputted to the 12th trellis encoder. Alternatively, if N is equal to 3,the block formatter 730 may arranged the output order, so that the databytes outputted from the symbol-byte converter 720 are inputted to the1st to 4th trellis encoders of the trellis encoding module 256, and thatthe data bytes outputted from the symbol-byte converter 751 are inputtedto the 5th to 8th trellis encoders, and that the data bytes outputtedfrom the symbol-byte converter 752 are inputted to the 9th to 12thtrellis encoders. At this point, the order of the data bytes outputtedfrom each symbol-byte converter may vary in accordance with the positionwithin the data group of the data other than the mobile service data,which are mixed with the mobile service data that are outputted fromeach symbol-byte converter.

FIG. 17 illustrates a detailed block diagram showing the structure of ablock processor according to another embodiment of the presentinvention. Herein, the block formatter is removed from the blockprocessor so that the operation of the block formatter may be performedby a group formatter. More specifically, the block processor of FIG. 17may include a byte-symbol converter 810, symbol-byte converters 820 and840, and a symbol interleaver 830. In this case, the output of eachsymbol-byte converter 820 and 840 is inputted to the group formatter850.

Also, the block processor may obtain a desired coding rate by addingsymbol interleavers and symbol-byte converters. If the system designerwishes a coding rate of 1/N, the block processor needs to be providedwith a total of N number of branches (or paths) including a branch (orpath), which is directly transmitted to the block formatter 850, and(N−1) number of symbol interleavers and symbol-byte convertersconfigured in a parallel structure with (N−1) number of branches. Atthis point, the group formatter 850 inserts place holders ensuring thepositions (or places) for the MPEG header, the non-systematic RS parity,and the main service data. And, at the same time, the group formatter850 positions the data bytes outputted from each branch of the blockprocessor.

The number of trellis encoders, the number of symbol-byte converters,and the number of symbol interleavers proposed in the present inventionare merely exemplary. And, therefore, the corresponding numbers do notlimit the spirit or scope of the present invention. It is apparent tothose skilled in the art that the type and position of each data bytebeing allocated to each trellis encoder of the trellis encoding module256 may vary in accordance with the data group format. Therefore, thepresent invention should not be understood merely by the examples givenin the description set forth herein. The mobile service data that areencoded at a coding rate of 1/N and outputted from the block processor303 are inputted to the group formatter 304. Herein, in the example ofthe present invention, the order of the output data outputted from theblock formatter of the block processor 303 are aligned and outputted inaccordance with the position of the data bytes within the data group.

Signaling Information Processing

The transmitter 200 according to the present invention may inserttransmission parameters by using a plurality of methods and in aplurality of positions (or places), which are then transmitted to thereceiving system. For simplicity, the definition of a transmissionparameter that is to be transmitted from the transmitter to thereceiving system will now be described. The transmission parameterincludes data group information, region information within a data group,the number of RS frames configuring a super frame (i.e., a super framesize (SFS)), the number of RS parity data bytes (P) for each columnwithin the RS frame, whether or not a checksum, which is added todetermine the presence of an error in a row direction within the RSframe, has been used, the type and size of the checksum if the checksumis used (presently, 2 bytes are added to the CRC), the number of datagroups configuring one RS frame—since the RS frame is transmitted to oneburst section, the number of data groups configuring the one RS frame isidentical to the number of data groups within one burst (i.e., burstsize (BS)), a turbo code mode, and a RS code mode.

Also, the transmission parameter required for receiving a burst includesa burst period—herein, one burst period corresponds to a value obtainedby counting the number of fields starting from the beginning of acurrent burst until the beginning of a next burst, a positioning orderof the RS frames that are currently being transmitted within a superframe (i.e., a permuted frame index (PFI)) or a positioning order ofgroups that are currently being transmitted within a RS frame (burst)(i.e., a group index (GI)), and a burst size. Depending upon the methodof managing a burst, the transmission parameter also includes the numberof fields remaining until the beginning of the next burst (i.e., time tonext burst (TNB)). And, by transmitting such information as thetransmission parameter, each data group being transmitted to thereceiving system may indicate a relative distance (or number of fields)between a current position and the beginning of a next burst.

The information included in the transmission parameter corresponds toexamples given to facilitate the understanding of the present invention.Therefore, the proposed examples do not limit the scope or spirit of thepresent invention and may be easily varied or modified by anyone skilledin the art. According to the first embodiment of the present invention,the transmission parameter may be inserted by allocating a predeterminedregion of the mobile service data packet or the data group. In thiscase, the receiving system performs synchronization and equalization ona received signal, which is then decoded by symbol units. Thereafter,the packet deformatter may separate the mobile service data and thetransmission parameter so as to detect the transmission parameter.According to the first embodiment, the transmission parameter may beinserted from the group formatter 304 and then transmitted.

According to the second embodiment of the present invention, thetransmission parameter may be multiplexed with another type of data. Forexample, when known data are multiplexed with the mobile service data, atransmission parameter may be inserted, instead of the known data, in aplace (or position) where a known data byte is to be inserted.Alternatively, the transmission parameter may be mixed with the knowndata and then inserted in the place where the known data byte is to beinserted. According to the second embodiment, the transmission parametermay be inserted from the group formatter 304 or from the packetformatter 306 and then transmitted.

According to a third embodiment of the present invention, thetransmission parameter may be inserted by allocating a portion of areserved region within a field synchronization segment of a transmissionframe. In this case, since the receiving system may perform decoding ona receiving signal by symbol units before detecting the transmissionparameter, the transmission parameter having information on theprocessing methods of the block processor 303 and the group formatter304 may be inserted in a reserved field of a field synchronizationsignal. More specifically, the receiving system obtains fieldsynchronization by using a field synchronization segment so as to detectthe transmission parameter from a pre-decided position. According to thethird embodiment, the transmission parameter may be inserted from thesynchronization multiplexer 240 and then transmitted.

According to the fourth embodiment of the present invention, thetransmission parameter may be inserted in a layer (or hierarchicalregion) higher than a transport stream (TS) packet. In this case, thereceiving system should be able to receive a signal and process thereceived signal to a layer higher than the TS packet in advance. At thispoint, the transmission parameter may be used to certify thetransmission parameter of a currently received signal and to provide thetransmission parameter of a signal that is to be received in a laterprocess.

In the present invention, the variety of transmission parametersassociated with the transmission signal may be inserted and transmittedby using the above-described methods according to the first to fourthembodiment of the present invention. At this point, the transmissionparameter may be inserted and transmitted by using only one of the fourembodiments described above, or by using a selection of theabove-described embodiments, or by using all of the above-describedembodiments. Furthermore, the information included in the transmissionparameter may be duplicated and inserted in each embodiment.Alternatively, only the required information may be inserted in thecorresponding position of the corresponding embodiment and thentransmitted. Furthermore, in order to ensure robustness of thetransmission parameter, a block encoding process of a short cycle (orperiod) may be performed on the transmission parameter and, then,inserted in a corresponding region. The method for performing ashort-period block encoding process on the transmission parameter mayinclude, for example, Kerdock encoding, BCH encoding, RS encoding, andrepetition encoding of the transmission parameter. Also, a combinationof a plurality of block encoding methods may also be performed on thetransmission parameter.

The transmission parameters may be grouped to create a block code of asmall size, so as to be inserted in a byte place allocated within thedata group for signaling and then transmitted. However, in this case,the block code passes through the block decoded from the receiving endso as to obtain a transmission parameter value. Therefore, thetransmission parameters of the turbo code mode and the RS code mode,which are required for block decoding, should first be obtained.Accordingly, the transmission parameters associated with a particularmode may be inserted in a specific section of a known data region. And,in this case, a correlation of with a symbol may be used for a fasterdecoding process. The receiving system refers to the correlation betweeneach sequence and the currently received sequences, thereby determiningthe encoding mode and the combination mode.

Meanwhile, when the transmission parameter is inserted in the fieldsynchronization segment region or the known data region and thentransmitted, and when the transmission parameter has passed through thetransmission channel, the reliability of the transmission parameter isdeteriorated. Therefore, one of a plurality of pre-defined patterns mayalso be inserted in accordance with the corresponding transmissionparameter. Herein, the receiving system performs a correlationcalculation between the received signal and the pre-defined patterns soas to recognize the transmission parameter. For example, it is assumedthat a burst including 5 data groups is pre-decided as pattern A basedupon an agreement between the transmitting system and the receivingsystem. In this case, the transmitting system inserts and transmitspattern A, when the number of groups within the burst is equal to 5.Thereafter, the receiving system calculates a correlation between thereceived data and a plurality of reference patterns including pattern A,which was created in advance. At this point, if the correlation valuebetween the received data and pattern A is the greatest, the receiveddata indicates the corresponding parameter, and most particularly, thenumber of groups within the burst. At this point, the number of groupsmay be acknowledged as 5. Hereinafter, the process of inserting andtransmitting the transmission parameter will now be described accordingto first, second, and third embodiments of the present invention.

First Embodiment

FIG. 18 illustrates a schematic diagram of the group formatter 304receiving the transmission parameter and inserting the receivedtransmission parameter in region A of the data group according to thepresent invention. Herein, the group formatter 304 receives mobileservice data from the block processor 303. Conversely, the transmissionparameter is processed with at least one of a data randomizing process,a RS frame encoding process, and a block processing process, and maythen be inputted to the group formatter 304. Alternatively, thetransmission parameter may be directly inputted to the group formatter304 without being processed with any of the above-mentioned processes.In addition, the transmission parameter may be provided from the servicemultiplexer 100. Alternatively, the transmission parameter may also begenerated and provided from within the transmitter 200. The transmissionparameter may also include information required by the receiving systemin order to receive and process the data included in the data group. Forexample, the transmission parameter may include data group information,and multiplexing information.

The group formatter 304 inserts the mobile service data and transmissionparameter which are to be inputted to corresponding regions within thedata group in accordance with a rule for configuring a data group. Forexample, the transmission parameter passes through a block encodingprocess of a short period and is, then, inserted in region A of the datagroup. Particularly, the transmission parameter may be inserted in apre-arranged and arbitrary position (or place) within region A. If it isassumed that the transmission parameter has been block encoded by theblock processor 303, the block processor 303 performs the same dataprocessing operation as the mobile service data, more specifically,either a ½-rate encoding or ¼-rate encoding process on the signalinginformation including the transmission parameter. Thereafter, the blockprocessor 303 outputs the processed transmission parameter to the groupformatter 304. Thereafter, the signaling information is also recognizedas the mobile service data and processed accordingly.

FIG. 19 illustrates a block diagram showing an example of the blockprocessor receiving the transmission parameter and processing thereceived transmission parameter with the same process as the mobileservice data. Particularly, FIG. 19 illustrates an example showing thestructure of FIG. 9 further including a signaling information provider411 and multiplexer 412. More specifically, the signaling informationprovider 411 outputs the signaling information including thetransmission parameter to the multiplexer 412. The multiplexer 412multiplexes the signaling information and the output of the RS frameencoder 302. Then, the multiplexer 412 outputs the multiplexed data tothe byte-bit converter 401.

The byte-bit converter 401 divides the mobile service data bytes orsignaling information byte outputted from the multiplexer 412 into bits,which are then outputted to the symbol encoder 402. The subsequentoperations are identical to those described in FIG. 9. Therefore, adetailed description of the same will be omitted for simplicity. If anyof the detailed structures of the block processor 303 shown in FIG. 12,FIG. 15, FIG. 16, and FIG. 17, the signaling information provider 411and the multiplexer 412 may be provided behind the byte-symbolconverter.

Second Embodiment

Meanwhile, when known data generated from the group formatter inaccordance with a pre-decided rule are inserted in a correspondingregion within the data group, a transmission parameter may be insertedin at least a portion of a region, where known data may be inserted,instead of the known data. For example, when a long known data sequenceis inserted at the beginning of region A within the data group, atransmission parameter may be inserted in at least a portion of thebeginning of region A instead of the known data. A portion of the knowndata sequence that is inserted in the remaining portion of region A,excluding the portion in which the transmission parameter is inserted,may be used to detect a starting point of the data group by thereceiving system. Alternatively, another portion of region A may be usedfor channel equalization by the receiving system.

In addition, when the transmission parameter is inserted in the knowndata region instead of the actual known data. The transmission parametermay be block encoded in short periods and then inserted. Also, asdescribed above, the transmission parameter may also be inserted basedupon a pre-defined pattern in accordance with the transmissionparameter. If the group formatter 304 inserts known data place holdersin a region within the data group, wherein known data may be inserted,instead of the actual known data, the transmission parameter may beinserted by the packet formatter 306. More specifically, when the groupformatter 304 inserts the known data place holders, the packet formatter306 may insert the known data instead of the known data place holders.Alternatively, when the group formatter 304 inserts the known data, theknown data may be directly outputted without modification.

FIG. 20 illustrates a block diagram showing the structure of a packetformatter 306 being expanded so that the packet formatter 306 can insertthe transmission parameter according to an embodiment of the presentinvention. More specifically, the structure of the packet formatter 306further includes a known data generator 351 and a signaling multiplexer352. Herein, the transmission parameter that is inputted to thesignaling multiplexer 352 may include information on the length of acurrent burst, information indicating a starting point of a next burst,positions in which the groups within the burst exist and the lengths ofthe groups, information on the time from the current group and the nextgroup within the burst, and information on known data.

The signaling multiplexer 352 selects one of the transmission parameterand the known data generated from the known data generator 351 and,then, outputs the selected data to the packet formatter 306. The packetformatter 306 inserts the known data or transmission parameter outputtedfrom the signaling multiplexer 352 into the known data place holdersoutputted from the data interleaver 305. Then, the packet formatter 306outputs the processed data. More specifically, the packet formatter 306inserts a transmission parameter in at least a portion of the known dataregion instead of the known data, which is then outputted. For example,when a known data place holder is inserted at a beginning portion ofregion A within the data group, a transmission parameter may be insertedin a portion of the known data place holder instead of the actual knowndata.

Also, when the transmission parameter is inserted in the known dataplace holder instead of the known data, the transmission parameter maybe block encoded in short periods and inserted. Alternatively, apre-defined pattern may be inserted in accordance with the transmissionparameter. More specifically, the signaling multiplexer 352 multiplexesthe known data and the transmission parameter (or the pattern defined bythe transmission parameter) so as to configure a new known datasequence. Then, the signaling multiplexer 352 outputs the newlyconfigured known data sequence to the packet formatter 306. The packetformatter 306 deletes the main service data place holder and RS parityplace holder from the output of the data interleaver 305, and creates amobile service data packet of 188 bytes by using the mobile servicedata, MPEG header, and the output of the signaling multiplexer. Then,the packet formatter 306 outputs the newly created mobile service datapacket to the packet multiplexer 240.

In this case, the region A of each data group has a different known datapattern. Therefore, the receiving system separates only the symbol in apre-arranged section of the known data sequence and recognizes theseparated symbol as the transmission parameter. Herein, depending uponthe design of the transmitting system, the known data may be inserted indifferent blocks, such as the packet formatter 306, the group formatter304, or the block processor 303. Therefore, a transmission parameter maybe inserted instead of the known data in the block wherein the knowndata are to be inserted.

According to the second embodiment of the present invention, atransmission parameter including information on the processing method ofthe block processor 303 may be inserted in a portion of the known dataregion and then transmitted. In this case, a symbol processing methodand position of the symbol for the actual transmission parameter symbolare already decided. Also, the position of the transmission parametersymbol should be positioned so as to be transmitted or received earlierthan any other data symbols that are to be decoded. Accordingly, thereceiving system may detect the transmission symbol before the datasymbol decoding process, so as to use the detected transmission symbolfor the decoding process.

Third Embodiment

Meanwhile, the transmission parameter may also be inserted in the fieldsynchronization segment region and then transmitted. FIG. 21 illustratesa block diagram showing the synchronization multiplexer being expandedin order to allow the transmission parameter to be inserted in the fieldsynchronization segment region. Herein, a signaling multiplexer 261 isfurther included in the synchronization multiplexer 260. Thetransmission parameter of the general VSB method is configured of 2fields. More specifically, each field is configured of one fieldsynchronization segment and 312 data segments. Herein, the first symbolsof a data segment correspond to the segment synchronization portion, andthe first data segment of each field corresponds to the fieldsynchronization portion.

One field synchronization signal is configured to have the length of onedata segment. The data segment synchronization pattern exists in thefirst 4 symbols, which are then followed by pseudo random sequences PN511, PN 63, PN 63, and PN 63. The next symbols include informationassociated with the VSB mode. Additionally, the 24 symbols that includeinformation associated with the VSB mode are followed by the remaining104 symbols, which are reserved symbols. Herein, the last 12 symbols ofa previous segment are copied and positioned as the last 12 symbols inthe reserved region. In other words, only the 92 symbols in the fieldsynchronization segment are the symbols that correspond to the actualreserved region.

Therefore, the signaling multiplexer 261 multiplexes the transmissionparameter with an already-existing field synchronization segment symbol,so that the transmission parameter can be inserted in the reservedregion of the field synchronization segment. Then, the signalingmultiplexer 261 outputs the multiplexed transmission parameter to thesynchronization multiplexer 260. The synchronization multiplexer 260multiplexes the segment synchronization symbol, the data symbols, andthe new field synchronization segment outputted from the signalingmultiplexer 261, thereby configuring a new transmission frame. Thetransmission frame including the field synchronization segment, whereinthe transmission parameter is inserted, is outputted to the transmissionunit 270. At this point, the reserved region within the fieldsynchronization segment for inserting the transmission parameter maycorrespond to a portion of or the entire 92 symbols of the reservedregion. Herein, the transmission parameter being inserted in thereserved region may, for example, include information identifying thetransmission parameter as the main service data, the mobile servicedata, or a different type of mobile service data.

If the information on the processing method of the block processor 303is transmitted as a portion of the transmission parameter, and when thereceiving system wishes to perform a decoding process corresponding tothe block processor 303, the receiving system should be informed of suchinformation on the block processing method in order to perform thedecoding process. Therefore, the information on the processing method ofthe block processor 303 should already be known prior to the blockdecoding process. Accordingly, as described in the third embodiment ofthe present invention, when the transmission parameter having theinformation on the processing method of the block processor 303 (and/orthe group formatter 304) is inserted in the reserved region of the fieldsynchronization signal and then transmitted, the receiving system iscapable of detecting the transmission parameter prior to performing theblock decoding process on the received signal.

Receiving System

FIG. 22 illustrates a block diagram showing a structure of a digitalbroadcast receiving system according to the present invention. Thedigital broadcast receiving system of FIG. 22 uses known datainformation, which is inserted in the mobile service data section and,then, transmitted by the transmitting system, so as to perform carriersynchronization recovery, frame synchronization recovery, and channelequalization, thereby enhancing the receiving performance. Referring toFIG. 22, the digital broadcast receiving system includes a tuner 901, ademodulator 902, an equalizer 903, a known data detector 904, a blockdecoder 905, a data deformatter 906, a RS frame decoder 907, aderandomizer 908, a data deinterleaver 909, a RS decoder 910, and a dataderandomizer 911. Herein, for simplicity of the description of thepresent invention, the data deformatter 906, the RS frame decoder 907,and the derandomizer 908 will be collectively referred to as a mobileservice data processing unit. And, the data deinterleaver 909, the RSdecoder 910, and the data derandomizer 911 will be collectively referredto as a main service data processing unit.

More specifically, the tuner 901 tunes a frequency of a particularchannel and down-converts the tuned frequency to an intermediatefrequency (IF) signal. Then, the tuner 901 outputs the down-converted IFsignal to the demodulator 902 and the known data detector 904. Thedemodulator 902 performs self gain control, carrier recovery, and timingrecovery processes on the inputted IF signal, thereby modifying the IFsignal to a baseband signal. Then, the demodulator 902 outputs the newlycreated baseband signal to the equalizer 903 and the known data detector904. The equalizer 903 compensates the distortion of the channelincluded in the demodulated signal and then outputs theerror-compensated signal to the block decoder 905.

At this point, the known data detector 904 detects the known sequenceplace inserted by the transmitting end from the input/output data of thedemodulator 902 (i.e., the data prior to the demodulation process or thedata after the demodulation process). Thereafter, the place informationalong with the symbol sequence of the known data, which are generatedfrom the detected place, is outputted to the demodulator 902 and theequalizer 903. Also, the known data detector 904 outputs a set ofinformation to the block decoder 905. This set of information is used toallow the block decoder 905 of the receiving system to identify themobile service data that are processed with additional encoding from thetransmitting system and the main service data that are not processedwith additional encoding. In addition, although the connection status isnot shown in FIG. 22, the information detected from the known datadetector 904 may be used throughout the entire receiving system and mayalso be used in the data deformatter 906 and the RS frame decoder 907.The demodulator 902 uses the known data symbol sequence during thetiming and/or carrier recovery, thereby enhancing the demodulatingperformance. Similarly, the equalizer 903 uses the known data so as toenhance the equalizing performance. Moreover, the decoding result of theblock decoder 905 may be fed-back to the equalizer 903, therebyenhancing the equalizing performance.

The equalizer 903 may perform channel equalization by using a pluralityof methods. An example of estimating a channel impulse response (CIR) soas to perform channel equalization will be given in the description ofthe present invention. Most particularly, an example of estimating theCIR in accordance with each region within the data group, which ishierarchically divided and transmitted from the transmitting system, andapplying each CIR differently will also be described herein.Furthermore, by using the known data, the place and contents of which isknown in accordance with an agreement between the transmitting systemand the receiving system, and the field synchronization data, so as toestimate the CIR, the present invention may be able to perform channelequalization with more stability.

Herein, the data group that is inputted for the equalization process isdivided into regions A to C, as shown in FIG. 6A. More specifically, inthe example of the present invention, each region A, B, and C arefurther divided into regions A1 to A5, regions B1 and B2, and regions C1to C3, respectively. Referring to FIG. 6A, the CIR that is estimatedfrom the field synchronization data in the data structure is referred toas CIR_FS. Alternatively, the CIRs that are estimated from each of the 5known data sequences existing in region A are sequentially referred toas CIR_N0, CIR_N1, CIR_N2, CIR_N3, and CIR_N4.

As described above, the present invention uses the CIR estimated fromthe field synchronization data and the known data sequences in order toperform channel equalization on data within the data group. At thispoint, each of the estimated CIRs may be directly used in accordancewith the characteristics of each region within the data group.Alternatively, a plurality of the estimated CIRs may also be eitherinterpolated or extrapolated so as to create a new CIR, which is thenused for the channel equalization process.

Herein, when a value F(A) of a function F(x) at a particular point A anda value F(B) of the function F(x) at another particular point B areknown, interpolation refers to estimating a function value of a pointwithin the section between points A and B. Linear interpolationcorresponds to the simplest form among a wide range of interpolationoperations. The linear interpolation described herein is merelyexemplary among a wide range of possible interpolation methods. And,therefore, the present invention is not limited only to the examples setforth herein.

Alternatively, when a value F(A) of a function F(x) at a particularpoint A and a value F(B) of the function F(x) at another particularpoint B are known, extrapolation refers to estimating a function valueof a point outside of the section between points A and B. Linearextrapolation is the simplest form among a wide range of extrapolationoperations. Similarly, the linear extrapolation described herein ismerely exemplary among a wide range of possible extrapolation methods.And, therefore, the present invention is not limited only to theexamples set forth herein.

More specifically, in case of region C1, any one of the CIR_N4 estimatedfrom a previous data group, the CIR_FS estimated from the current datagroup that is to be processed with channel equalization, and a new CIRgenerated by extrapolating the CIR_FS of the current data group and theCIR_N0 may be used to perform channel equalization. Alternatively, incase of region B1, a variety of methods may be applied as described inthe case for region C1. For example, a new CIR created by linearlyextrapolating the CIR_FS estimated from the current data group and theCIR_N0 may be used to perform channel equalization. Also, the CIR_FSestimated from the current data group may also be used to performchannel equalization. Finally, in case of region A1, a new CIR may becreated by interpolating the CIR_FS estimated from the current datagroup and CIR_N0, which is then used to perform channel equalization.Furthermore, any one of the CIR_FS estimated from the current data groupand CIR_N0 may be used to perform channel equalization.

In case of regions A2 to A5, CIR_N(i−1) estimated from the current datagroup and CIR_N(i) may be interpolated to create a new CIR and use thenewly created CIR to perform channel equalization. Also, any one of theCIR_N(i−1) estimated from the current data group and the CIR_N(i) may beused to perform channel equalization. Alternatively, in case of regionsB2, C2, and C3, CIR_N3 and CIR_N4 both estimated from the current datagroup may be extrapolated to create a new CIR, which is then used toperform the channel equalization process. Furthermore, the CIR_N4estimated from the current data group may be used to perform the channelequalization process. Accordingly, an optimum performance may beobtained when performing channel equalization on the data inserted inthe data group. The methods of obtaining the CIRs required forperforming the channel equalization process in each region within thedata group, as described above, are merely examples given to facilitatethe understanding of the present invention. A wider range of methods mayalso be used herein. And, therefore, the present invention will not onlybe limited to the examples given in the description set forth herein.

Meanwhile, if the data being inputted to the block decoder 905 afterbeing channel equalized from the equalizer 903 correspond to the mobileservice data having additional encoding and trellis encoding performedthereon by the transmitting system, trellis decoding and additionaldecoding processes are performed on the inputted data as inverseprocesses of the transmitting system. Alternatively, if the data beinginputted to the block decoder 905 correspond to the main service datahaving only trellis encoding performed thereon, and not the additionalencoding, only the trellis decoding process is performed on the inputteddata as the inverse process of the transmitting system.

The data group decoded by the block decoder 905 is inputted to the datadeformatter 906, and the main service data are inputted to the datadeinterleaver 909. According to another embodiment, the main data mayalso bypass the block decoder 905 so as to be directly inputted to thedata deinterleaver 909. In this case, a trellis decoder for the mainservice data should be provided before the data deinterleaver 909. Whenthe block decoder 905 outputs the data group to the data deformatter906, the known data, trellis initialization data, and MPEG header, whichare inserted in the data group, and the RS parity, which is added by theRS encoder/non-systematic RS encoder or non-systematic RS encoder of thetransmitting system, are removed. Then, the processed data are outputtedto the data deformatter 906. Herein, the removal of the data may beperformed before the block decoding process, or may be performed duringor after the block decoding process. If the transmitting system includessignaling information in the data group upon transmission, the signalinginformation is outputted to the data deformatter 906.

More specifically, if the inputted data correspond to the main servicedata, the block decoder 905 performs Viterbi decoding on the inputteddata so as to output a hard decision value or to perform a hard-decisionon a soft decision value, thereby outputting the result. Meanwhile, ifthe inputted data correspond to the mobile service data, the blockdecoder 905 outputs a hard decision value or a soft decision value withrespect to the inputted mobile service data. In other words, if theinputted data correspond to the mobile service data, the block decoder905 performs a decoding process on the data encoded by the blockprocessor and trellis encoding module of the transmitting system.

At this point, the RS frame encoder of the pre-processor included in thetransmitting system may be viewed as an external code. And, the blockprocessor and the trellis encoder may be viewed as an internal code. Inorder to maximize the performance of the external code when decodingsuch concatenated codes, the decoder of the internal code should outputa soft decision value. Therefore, the block decoder 905 may output ahard decision value on the mobile service data. However, when required,it may be more preferable for the block decoder 905 to output a softdecision value.

Meanwhile, the data deinterleaver 909, the RS decoder 910, and thederandomizer 911 are blocks required for receiving the main servicedata. Therefore, the above-mentioned blocks may not be required in thestructure of a digital broadcast receiving system that only receives themobile service data. The data deinterleaver 909 performs an inverseprocess of the data interleaver included in the transmitting system. Inother words, the data deinterleaver 909 deinterleaves the main servicedata outputted from the block decoder 905 and outputs the deinterleavedmain service data to the RS decoder 910. The RS decoder 910 performs asystematic RS decoding process on the deinterleaved data and outputs theprocessed data to the derandomizer 911. The derandomizer 911 receivesthe output of the RS decoder 910 and generates a pseudo random data byteidentical to that of the randomizer included in the digital broadcasttransmitting system. Thereafter, the derandomizer 911 performs a bitwiseexclusive OR (XOR) operation on the generated pseudo random data byte,thereby inserting the MPEG synchronization bytes to the beginning ofeach packet so as to output the data in 188-byte main service datapacket units.

Meanwhile, the data being outputted from the block decoder 905 to thedata deformatter 906 are inputted in the form of a data group. At thispoint, the data deformatter 906 already knows the structure of the datathat are to be inputted and is, therefore, capable of identifying thesignaling information, which includes the system information, and themobile service data from the data group. Thereafter, the datadeformatter 906 outputs the identified signaling information to a blockfor processing signaling information (not shown) and outputs theidentified mobile service data to the RS frame decoder 907. Morespecifically, the RS frame decoder 907 receives only the RS encoded andCRC encoded mobile service data that are transmitted from the datadeformatter 906.

The RS frame encoder 907 performs an inverse process of the RS frameencoder included in the transmitting system so as to correct the errorwithin the RS frame. Then, the RS frame decoder 907 adds the 1-byte MPEGsynchronization service data packet, which had been removed during theRS frame encoding process, to the error-corrected mobile service datapacket. Thereafter, the processed data packet is outputted to thederandomizer 908. The operation of the RS frame decoder 907 will bedescribed in detail in a later process. The derandomizer 908 performs aderandomizing process, which corresponds to the inverse process of therandomizer included in the transmitting system, on the received mobileservice data. Thereafter, the derandomized data are outputted, therebyobtaining the mobile service data transmitted from the transmittingsystem. Hereinafter, detailed operations of the RS frame decoder 907will now be described.

FIG. 23 illustrates a series of exemplary step of an error correctiondecoding process of the RS frame decoder 907 according to the presentinvention. More specifically, the RS frame decoder 907 groups mobileservice data bytes received from the data deformatter 906 so as toconfigure an RS frame. The mobile service data correspond to data RSencoded and CRC encoded from the transmitting system. FIG. 23(a)illustrates an example of configuring the RS frame. More specifically,the transmitting system divided the RS frame having the size of(N+2)*235 to 30*235 byte blocks. When it is assumed that each of thedivided mobile service data byte blocks is inserted in each data groupand then transmitted, the receiving system also groups the 30*235 mobileservice data byte blocks respectively inserted in each data group,thereby configuring an RS frame having the size of (N+2)*235. Forexample, when it is assumed that an RS frame is divided into 18 30*235byte blocks and transmitted from a burst section, the receiving systemalso groups the mobile service data bytes of 18 data groups within thecorresponding burst section, so as to configure the RS frame.Furthermore, when it is assumed that N is equal to 538 (i.e., N−538),the RS frame decoder 907 may group the mobile service data bytes withinthe 18 data groups included in a burst so as to configure a RS framehaving the size of 540*235 bytes.

Herein, when it is assumed that the block decoder 905 outputs a softdecision value for the decoding result, the RS frame decoder 907 maydecide the ‘0’ and ‘1’ of the corresponding bit by using the codes ofthe soft decision value. 8 bits that are each decided as described aboveare grouped to create 1 data byte. If the above-described process isperformed on all soft decision values of the 18 data groups included ina single burst, the RS frame having the size of 540*235 bytes may beconfigured. Additionally, the present invention uses the soft decisionvalue not only to configure the RS frame but also to configure areliability map. Herein, the reliability map indicates the reliabilityof the corresponding data byte, which is configured by grouping 8 bits,the 8 bits being decided by the codes of the soft decision value.

For example, when the absolute value of the soft decision value exceedsa pre-determined threshold value, the value of the corresponding bit,which is decided by the code of the corresponding soft decision value,is determined to be reliable. Conversely, when the absolute value of thesoft decision value does not exceed the pre-determined threshold value,the value of the corresponding bit is determined to be unreliable.Thereafter, if even a single bit among the 8 bits, which are decided bythe codes of the soft decision value and group to configure 1 data byte,is determined to be unreliable, the corresponding data byte is marked onthe reliability map as an unreliable data byte.

Herein, determining the reliability of 1 data byte is only exemplary.More specifically, when a plurality of data bytes (e.g., at least 4 databytes) are determined to be unreliable, the corresponding data bytes mayalso be marked as unreliable data bytes within the reliability map.Conversely, when all of the data bits within the 1 data byte aredetermined to be reliable (i.e., when the absolute value of the softdecision values of all bits included in the 1 data byte exceed thepredetermined threshold value), the corresponding data byte is marked tobe a reliable data byte on the reliability map. Similarly, when aplurality of data bytes (e.g., at least 4 data bytes) are determined tobe reliable, the corresponding data bytes may also be marked as reliabledata bytes within the reliability map. The numbers proposed in theabove-described example are merely exemplary and, therefore, do notlimit the scope or spirit of the present invention.

The process of configuring the RS frame and the process of configuringthe reliability map both using the soft decision value may be performedat the same time. Herein, the reliability information within thereliability map is in a one-to-one correspondence with each byte withinthe RS frame. For example, if a RS frame has the size of 540*235 bytes,the reliability map is also configured to have the size of 540*235bytes. FIG. 23(a′) illustrates the process steps of configuring thereliability map according to the present invention. Meanwhile, if a RSframe is configured to have the size of (N+2)*235 bytes, the RS framedecoder 907 performs a CRC syndrome checking process on thecorresponding RS frame, thereby verifying whether any error has occurredin each row. Subsequently, as shown in FIG. 23(b), a 2-byte checksum isremoved to configure an RS frame having the size of N*235 bytes. Herein,the presence (or existence) of an error is indicated on an error flagcorresponding to each row. Similarly, since the portion of thereliability map corresponding to the CRC checksum has hardly anyapplicability, this portion is removed so that only N*235 number of thereliability information bytes remain, as shown in FIG. 23(b′).

After performing the CRC syndrome checking process, the RS frame decoder907 performs RS decoding in a column direction. Herein, a RS erasurecorrection process may be performed in accordance with the number of CRCerror flags. More specifically, as shown in FIG. 23(c), the CRC errorflag corresponding to each row within the RS frame is verified.Thereafter, the RS frame decoder 907 determines whether the number ofrows having a CRC error occurring therein is equal to or smaller thanthe maximum number of errors on which the RS erasure correction may beperformed, when performing the RS decoding process in a columndirection. The maximum number of errors corresponds to a number ofparity bytes inserted when performing the RS encoding process. In theembodiment of the present invention, it is assumed that 48 parity byteshave been added to each column.

If the number of rows having the CRC errors occurring therein is smallerthan or equal to the maximum number of errors (i.e., 48 errors accordingto this embodiment) that can be corrected by the RS erasure decodingprocess, a (235,187)-RS erasure decoding process is performed in acolumn direction on the RS frame having 235 N-byte rows, as shown inFIG. 23(d). Thereafter, as shown in FIG. 23(f), the 48-byte parity datathat have been added at the end of each column are removed. Conversely,however, if the number of rows having the CRC errors occurring thereinis greater than the maximum number of errors (i.e., 48 errors) that canbe corrected by the RS erasure decoding process, the RS erasure decodingprocess cannot be performed. In this case, the error may be corrected byperforming a general RS decoding process. In addition, the reliabilitymap, which has been created based upon the soft decision value alongwith the RS frame, may be used to further enhance the error correctionability (or performance) of the present invention.

More specifically, the RS frame decoder 907 compares the absolute valueof the soft decision value of the block decoder 905 with thepre-determined threshold value, so as to determine the reliability ofthe bit value decided by the code of the corresponding soft decisionvalue. Also, 8 bits, each being determined by the code of the softdecision value, are grouped to form 1 data byte. Accordingly, thereliability information on this 1 data byte is indicated on thereliability map. Therefore, as shown in FIG. 23(e), even though aparticular row is determined to have an error occurring therein basedupon a CRC syndrome checking process on the particular row, the presentinvention does not assume that all bytes included in the row have errorsoccurring therein. The present invention refers to the reliabilityinformation of the reliability map and sets only the bytes that havebeen determined to be unreliable as erroneous bytes. In other words,with disregard to whether or not a CRC error exists within thecorresponding row, only the bytes that are determined to be unreliablebased upon the reliability map are set as erasure points.

According to another method, when it is determined that CRC errors areincluded in the corresponding row, based upon the result of the CRCsyndrome checking result, only the bytes that are determined by thereliability map to be unreliable are set as errors. More specifically,only the bytes corresponding to the row that is determined to haveerrors included therein and being determined to be unreliable based uponthe reliability information, are set as the erasure points. Thereafter,if the number of error points for each column is smaller than or equalto the maximum number of errors (i.e., 48 errors) that can be correctedby the RS erasure decoding process, an RS erasure decoding process isperformed on the corresponding column. Conversely, if the number oferror points for each column is greater than the maximum number oferrors (i.e., 48 errors) that can be corrected by the RS erasuredecoding process, a general decoding process is performed on thecorresponding column.

More specifically, if the number of rows having CRC errors includedtherein is greater than the maximum number of errors (i.e., 48 errors)that can be corrected by the RS erasure decoding process, either an RSerasure decoding process or a general RS decoding process is performedon a column that is decided based upon the reliability information ofthe reliability map, in accordance with the number of erasure pointswithin the corresponding column. For example, it is assumed that thenumber of rows having CRC errors included therein within the RS frame isgreater than 48. And, it is also assumed that the number of erasurepoints decided based upon the reliability information of the reliabilitymap is indicated as 40 erasure points in the first column and as 50erasure points in the second column. In this case, a (235,187)-RSerasure decoding process is performed on the first column.Alternatively, a (235,187)-RS decoding process is performed on thesecond column. When error correction decoding is performed on all columndirections within the RS frame by using the above-described process, the48-byte parity data which were added at the end of each column areremoved, as shown in FIG. 23(f).

As described above, even though the total number of CRC errorscorresponding to each row within the RS frame is greater than themaximum number of errors that can be corrected by the RS erasuredecoding process, when the number of bytes determined to have a lowreliability level, based upon the reliability information on thereliability map within a particular column, while performing errorcorrection decoding on the particular column. Herein, the differencebetween the general RS decoding process and the RS erasure decodingprocess is the number of errors that can be corrected. Morespecifically, when performing the general RS decoding process, thenumber of errors corresponding to half of the number of parity bytes(i.e., (number of parity bytes)/2) that are inserted during the RSencoding process may be error corrected (e.g., 24 errors may becorrected). Alternatively, when performing the RS erasure decodingprocess, the number of errors corresponding to the number of paritybytes that are inserted during the RS encoding process may be errorcorrected (e.g., 48 errors may be corrected).

After performing the error correction decoding process, as describedabove, a RS frame configured of 187 N-byte rows (or packets) maybeobtained, as shown in FIG. 23(f). Furthermore, the RS frame having thesize of N*187 bytes is sequentially outputted in N number of 187-byteunits. Herein, as shown in FIG. 23(g), the 1-byte MPEG synchronizationbyte that was removed by the transmitting system is added at the end ofeach 187-byte packet, thereby outputting 188-byte mobile service datapackets.

As described above, the digital broadcasting system and the dataprocessing method according to the present invention have the followingadvantages. More specifically, the digital broadcasting receiving systemand method according to the present invention is highly protectedagainst (or resistant to) any error that may occur when transmittingmobile service data through a channel. And, the present invention isalso highly compatible to the conventional receiving system. Moreover,the present invention may also receive the mobile service data withoutany error even in channels having severe ghost effect and noise.

Additionally, by inserting known data in a particular position (orplace) within a data region and transmitting the processed data, thereceiving performance of the receiving system may be enhanced even in achannel environment that is liable to frequent changes. Also, bymultiplexing mobile service data with main service data into a burststructure, the power consumption of the receiving system may be reduced.Furthermore, the present invention is even more effective when appliedto mobile and portable receivers, which are also liable to a frequentchange in channel and which require protection (or resistance) againstintense noise.

Hereinafter, an example of transmitting/receiving multiplexinginformation for the main service data and the mobile service data in thecase where the main service data and the mobile service data aremultiplexed and the multiplexed data is transmitted in the broadcasttransmitting/receiving system will be described. The multiplexinginformation may be provided to the receiver in the form of a tableincluding at least one section and, hereinafter, will be referred to asprogram table information. For example, program specific information(PSI)/program and system information protocol (PSIP) may become theprogram table information. Hereinafter, a fixed reception channelindicates a channel which can allow the broadcasting system totransmit/receive the main service data and a mobile reception channelindicates a channel which can allow the broadcasting system totransmit/receive the mobile service data.

In the case where the main service data and the mobile service data aremultiplexed and the multiplexed data is transmitted, program tableinformation of the main service data and program table information ofthe mobile service data may be respectively multiplexed with the mainservice data and the mobile service data by the same packet identifierand the multiplexed data may be transmitted. That is, the program tableinformation including multiplexing information for the main service dataand the mobile service data is multiplexed with the main service dataand the mobile service data and the multiplexed data is transmitted. Inother words, the PSI/PSIP information within the main service data andthe PSI/PSIP information within the mobile service data become the sameprogram table information and have the same packet identifier, and theprogram table information includes information which can parse both themain service data and the mobile service data.

For example, if the program table information is a virtual channel table(VCT), the VCT may include information about a virtual channel formed bythe main service data and information about a virtual channel formed bythe mobile service data. The VCT may be included in the mobile servicedata section and the main service data section and may be multiplexed.Accordingly, although the broadcasting signal receiving device parsesthe VCT from at least one of the mobile service data section and themain service data section, it is possible to obtain the informationabout the virtual channel included in the mobile service data sectionand the main service data section through the VCT.

FIG. 24 is a view showing an example of transmitting program tableinformation including multiplexing information for the main service dataand the mobile service data. FIG. 24 is similar to FIG. 2, butconfiguration information for both the main service data and the mobileservice data are included in the same program table information and theprogram table information are respectively transmitted by multiplexingthe main service data and the mobile service data. The program tableinformation (PSI/PSIP for main and mobile service) includes themultiplexing information for the main service data and the mobileservice data.

For example, the VCT included in the fixed reception channel and the VCTincluded in the mobile reception channel include multiplexing andconfigurative information for the mobile service data and the mainservice data, and may be respectively transmitted with the mobileservice data and the main service data.

Although FIG. 2 shows the case where the service multiplexer transmitsthe broadcasting signal to the transmitter, the program tableinformation including the multiplexing information for the main servicedata and the mobile service data is encoded by the PSIP encoder for theunited PSI/PSIP with main and mobile service as shown in FIG. 24 evenwhen the transmitter transmits the broadcasting signal to the broadcastreceiving system. The encoded program table information may be includedin the main service data and the mobile service data and may betransmitted. Hereinafter, the embodiment of the multiplexed programtable information will be described with reference to the accompanyingdrawings.

FIG. 25 is a view showing an example of a channel operation of atransmission program. FIG. 25 is a conceptual view of a case where abroadcasting station transmits broadcast service data to a physicalchannel. In the example of FIG. 25, it is assumed that the broadcastingstation transmits a fixed reception channel 30-1 and mobile receptionchannels 30-5 and 30-6 to a physical channel 15 within a broadcasttransmission channel (it is assumed that the RF band of the channel 15is 620.31 MHz in FIG. 24). The main service data is transmitted throughthe fixed reception channel and the mobile service data is transmittedthrough the mobile service data.

In the example of FIG. 25, one video service and two audio services aredelivered through the fixed reception channel 30-1 (major channel-minorchannel) Here, it is assumed that the packet identifier (PID) of thevideo elementary stream (ES) for the video service of the channel 30-1is 0x31, the PID of the audio ES for the Korean audio service thereof is0x34, and the PID of the audio ES for the English audio service thereofis 0x35. It is assumed that the video service of the channel 30-1provides a video service with high-definition (HD) image quality.

In the example of FIG. 25, one SD video service, one audio service andone data service are delivered through the mobile reception channel30-5. The PID of the video ES of the channel 30-5 is 0x51, the PID ofthe audio ES thereof is 0x54, and the PID of the data ES thereof is0x78.

In the example of FIG. 25, one SD video service and two audio servicesare delivered through the mobile reception channel 30-6. It is assumedthat the PID of the video ES of the channel 30-6 is 0x61, the PID of theES of the Korean audio service thereof is 0x64, and the PID of the ES ofthe English audio service thereof is 0x65. The structure of the virtualchannel shown in FIG. 25 is also used in the following examples. In thecase where information about a plurality of fixed reception channels andinformation about a plurality of mobile reception channels aretransmitted to one physical channel like the example of FIG. 25, theinformation about the channels may be included in the same program tableinformation and may be transmitted. The same type of program tableinformation, for example, the VCT, may have the same PID in the fixedreception channel and the mobile reception channel. The program tableinformation according to the PSI information such as PMT and the PSIPinformation such as VCT, MGT, EIT, ETT, SST and RRT may be transmittedthrough the mobile reception channel and the fixed reception channel.

FIG. 26 is a conceptual view of programs provided as services in aphysical channel band in the case where broadcasting service data shownin FIG. 25 is included in the physical channel and is transmitted. If itis assumed that the bandwidth of the entire channel is 19.39 Mbps, themain service data is transmitted in a portion of the entire bandwidth(19.39-K Mbps in FIG. 26) and the mobile service data is transmitted inanother portion thereof (K Mbps in FIG. 26). In the transmissionbandwidth of the main service data, one video ES and the program tableinformation (PSI/PSIP) shown in FIG. 25 are included. In contrast, inthe transmission bandwidth of the mobile service data, the video ES, theaudio ES and the data ES for the broadcasting service of the channel30-5, and the video ES, the audio ES and the audio ES for thebroadcasting service of the channel 30-6 are included, and the programtable information (PSI/PSIP) is included.

Here, the PSI/PSIP for the main service data and the mobile service dataincludes the same information. That is, the program table informationsuch as the PSI/PSIP may describe the main service data, describe themobile service data, and have the identifier for identifying the mainservice data and the mobile service data.

Meanwhile, as described with reference to FIG. 24, null packets may betransmitted to the mobile service data region such that the mobileservice data is maintained at K Mbps. FIG. 26 shows the case where thenull packets are transmitted to the mobile service data region so as tobe matched to a transmission rate of the broadcasting service data.

FIGS. 27 to 33 show the case where the program table informationmultiplexed in the main service data and the mobile service data sectionhas the same contents and the same PID.

FIG. 27 is a view showing an example of the PMT multiplexed in theservice data. The PMT of FIG. 27 may describe the program according tothe mobile service data. Although the program according to the mobileservice data is described, the PMT may be multiplexed with the mainservice data and the multiplexed data may be transmitted like theexample of FIG. 24 (in FIG. 24, the same PMT is multiplexed in themobile service data and is transmitted).

The header of the PMT of FIG. 27 includes table_id,section_syntax_indicator, ‘0’, reserved, section_length, program_number,reserved, version_number, current_next_indicator, section_number,last_section_number, reserved, and PCR_PID. The table_id is the tableidentifier of the PMT and, for example, the table_id of the PMT may be0x02. The section_syntax_indicator has a value according to the syntaxof MPEG long-form. A field in which “0” is set according to thedefinition of the PMT and the reserved field follow. The section_lengthindicates the length of the PMT section and the program_number isinformation equal to the PAT and becomes the program number. Then,two-bit reserved field and the version_number, in which the versioninformation for checking whether the table is updated is set, follow.The current_next_indicator is an indicator indicating whether thecurrent table section can be applied. The section_number indicates theserial number of the segment when the PMT is segmented into sections,and the last_section_number indicates the section number of the lastsegment. The PID delivering the program clock reference (PCR) of thecurrent program is set after 3-bit reserved region having a value of 1.

The PMT includes a program descriptor describing respective programs anda stream descriptor describing streams in each of the programs. Theprogram descriptor (a) may include a descriptor indicating whether theprogram included in the broadcasting signal is transmitted through themobile service data. Accordingly, the PMT shown in FIG. 27 may bemultiplexed in the mobile service data and the main service data and thePMT may include the identifier for identifying the main/mobile servicedata. The detailed example thereof is shown in FIG. 28.

FIG. 28 is a view showing a descriptor which is included in the programtable information and can parse information for identifying themobile/main service data. Although the identifier shown in FIG. 28 maybe included in the PMT and may be transmitted as shown in FIG. 27 or maybe transmitted through other program table information. The descriptorof FIG. 28 (hereinafter, referred to as mobile_service_descriptor)includes descriptor_tag which is the descriptor identifier anddescriptor_length which is the descriptor length. In addition, thedescriptor may include at least one of modulation_mode and service_typewhich may be the identifiers for identifying the mobile/main servicedata. The modulation_mode is an identifier for identifying whether themodulation mode is the modulation mode for the main service data or themodulation mode for the mobile service data. The modulation_mode isshown in FIG. 31 in detail. The service_type indicates the service typeof the program and may indicate whether the service type is the servicetype according to the main service type or the service type according tothe mobile service data. The service_type is shown in FIG. 32 in detail.That is, as shown in FIG. 27, the PMT may be multiplexed in the mobileservice data section and the main service data section and include thedescriptor information for identifying the mobile service data. In FIG.28, burst_id indicates the identifier of the burst described in FIG. 8.The broadcast receiving system identifies the burst section, in which adesired broadcasting program is multiplexed, using the identifier of theburst and receives the broadcasting signal only in the burst section,thereby reducing power consumption. The mobile_service_descriptorincluded in the program table information may include the informationfor identifying the mobile service data and the main service data andmay include the identifier of the burst including the mobile servicedata.

FIG. 29 is a view showing an example of multiplexing the program tableinformation for the main service data and the mobile service data withbroadcasting data and transmitting the multiplexed data. The example oftransmitting the multiplexing information for the main service data andthe mobile service data will be described with reference to FIG. 29.

In the example of FIG. 29, the PID of the PAT including the programinformation for the main service data and the mobile service data is0x0000. It is assumed that the transport stream ID for the transportstream of the main service data and the mobile service data is any value(ttt1) in FIG. 29. According to the example of FIG. 25, since the numberof programs for the main service data is 1 and the number of programsfor the mobile service data is 2, the “Num of Program” of FIG. 29 is 3which is the sum of the number of programs for the main service and thenumber of programs for the mobile service.

The PAT includes the PIDs of the PMTs for the programs. The programs maybe transmitted as the main service data or the mobile service data. Inthe example of FIG. 29, the PID of the PMT for the main service data isppp1 (channel 30-1) and the PIDs of the PMT for the mobile service dataare ppp2 (channel 30-5) and ppp3 (channel 30-6). The PMT (PMT1 of FIG.29) for the main service program of the channel 30-1 includes 1 as thevalue of the program number and includes the ES packet identifier (ESPID=0x31) for the elementary stream of which the stream type is video.The PMT1 includes the ES PID (0x34) for the Korean audio stream type andthe ES PID (0x35) for the English audio stream type.

The PMT (PMT2 of FIG. 29) for the program according to the mobileservice of the channel 30-5 includes 5 as the value of the programnumber and the stream information parsed by the PMT (PMT2 of FIG. 29) isthe ES PID (0x51) for the elementary stream of which the stream type isvideo. The PMT2 includes the ES PID (0x54) for the Korean audio streamtype and the ES PID (0x78) for the data stream type.

In the example of FIG. 29, the PMTS for the program according to themobile service transmitted through the channel 30-6 includes 6 as thevalue of the program number and includes the ES PID (0x61) for the videostream type, the ES PID (0x64) for the Korean audio stream, and the ESPID (0x65) for the English audio stream. Although not shown in FIG. 29,PMT2 and PMT3 for the mobile service data may include the descriptorshown in FIG. 28. Accordingly, the program table information shown inFIG. 29 is included in the main service data and the mobile servicedata, the program table information may describe the main service dataand the mobile service data and may include the respective identifiersfor the main service data and the mobile service data. The program tableinformation shown in FIG. 29, such as the PAT and PMT, is encoded by theprogram table information (PSIP) encoder. The encoded program tableinformation may be respectively multiplexed with the main service dataand the mobile service data by a main service multiplexer and a mobileservice multiplexer and the multiplexed data is transmitted.Accordingly, the same program table information may be transmitted inthe mobile service data section and the main service data section.

FIG. 30 is a view showing the VCT in the program table information.Similar to FIG. 29, the VCTs which are respectively multiplexed in themobile service data and the main service data may be transmitted. TheVCTs which are respectively multiplexed in the main/mobile service datawill be described with reference to FIG. 30. The VCT includes the headeraccording to the transport format of the MPEG-2 system.

The header of the VCT may include table_id, section_syntax_indicator,private_indicator, reserved, section_length, transport_stream_id,reserved, version_number, current_next_indicator, section_number,last_section_number, and protocol_version. The table_id is the tableidentifier of the VCT and the table_id of the terrestrial virtualchannel table (TVCT) is, for example, 0xC8. The section_syntax_indicatorhas a value according to the syntax of the MPEG long-form. The VCTincludes the private_indicator, which is set to 1 according to thedefinition of the PSIP, and the 2-bit reserved region which followsthereafter. The section_length indicates the length of the VCT sectionand the transport_stream_id indicates the TSID value of the PAT. The VCTincludes the 2-bit reserved region which follows after thetransport_stream_id and the version_number has the version informationfor checking whether the table is updated. The current_next_indicator isan indicator indicating whether the current table section can beapplied. The section_number indicates the serial number of the segmentwhen the VCT is segmented into sections, and the last_section_numberindicates the section number of the last segment. The protocol_versionindicates the protocol version of the table section.

In the case where the mobile service data and the main service data aretransmitted through the same physical channel, thenum_channel_in_section indicates the number of virtual channels includedin one physical channel. Accordingly, if the fixed reception channel andthe mobile reception channel are included in one physical channel, thenum_channel_in_section of the VCT for the fixed reception channelbecomes the sum of the number of programs for the main service and thenumber of programs for the mobile service.

The VCT includes information about major_channel_number andminor_channel_number related to the virtual channel. In addition, theVCT may include the modulation mode which is the modulation modeinformation of the carrier of the virtual channel according to thenum_channel_in_section (that is, according to the virtual channel). Forexample, the modulation mode may indicate the information according tothe modulation mode such as 8-VSB, 16-VSB, 64 QAM and 256 QAM. Themodulation mode may have different values with respect to the mobilereception channel and the fixed reception channel according to thenum_channel_in_section. For example, in the virtual channel for the mainservice data, the modulation mode may have a value indicating 8-VSB or16-VSB. In contrast, in the virtual channel for the mobile service data,the modulation mode may have a value indicating the modulation mode ofthe mobile service data. With respect to the virtual channel for themain service data and the virtual channel for the mobile service data,respective modulation mode information values may be set. That is, thebroadcast receiving system may use the modulation mode for the VCT asthe identifiers for identifying the virtual channel for the mobileservice data and the virtual channel for the main service data. Thedetailed example set in the modulation mode in the VCT is shown in FIG.31.

As another example, the service_type is the information indicating theservice type transmitted through the virtual channel. The service typeinformation of the virtual channel for the mobile service data and theservice type information of the virtual channel for the main servicedata may be included in the VCT according to the num_channels_in_sectionof the VCT. Accordingly, the service_type of the VCT may be theidentifiers for identifying the mobile service and the main service withrespect to the virtual channel. The detailed example thereof is shown inFIG. 32.

As another example, the service_location_descriptor which is thedescriptor of the VCT may include information for identifying thevirtual channel for the mobile service data and the virtual channel forthe main service data (that is, the virtual channel according to thenum_channels_in_section). With respect to the mobile reception channel,the service_location descriptor may include the audio ES, the video ESand the data ES of the mobile reception channel. In contrast, withrespect to the fixed reception channel, the service_location_descriptorof the VCT may include the stream ES PID information of the virtualchannel through which the main service data is transmitted. Accordingly,although the same VCT is included in the main service data and themobile service data, the broadcast receiving system can identify thevirtual channels for the main service and the mobile service by theservice_location_descriptor.

The VCT including the information for identifying the main service dataand the mobile service data is multiplexed with the main service dataand the mobile service data and the multiplexed data is transmitted.

FIG. 31 is a view showing the modulation mode of the broadcastingsignal. Referring to FIG. 30, the modulation mode will be described. Inthe modulation mode delivered by the VCT, 0x00 indicates “reserved”,0x01 indicates “analog”, 0x02 indicates “SCTE_mode_1”, 0x03 indicates“SCTE_mode_2”, 0x04 indicates “ATSC (8 VSB), and 0x05 indicates “ATSC(16 VSB). For example, the modulation mode of the signal (mobile servicedata) transmitted through the mobile reception channel may be set to0x06 in the virtual channel loop (num_channels_in_section) of the VCT.In the example of FIG. 31, the value of the modulation mode of themobile reception virtual channel is set to 0x06 (indicated by mobile-VSBin FIG. 30). In the example of FIG. 31, 0x07 to 0x7F indicate thereserved regions for future and 0x80 to 0xFF indicate the user privateregions. In the example of FIG. 31, the VCT may include informationabout the modulation_mode for identifying the virtual channel for themobile service data and the virtual channel for the main service datamay include the respective modulation modes. In addition, the VCTincluding the information about the virtual channel for the mobileservice data and the virtual channel for main service data ismultiplexed in the mobile service data and the main service data and istransmitted. The mobile service data and the main service data may beidentified according to the modulation mode shown in FIG. 31.

FIG. 32 is a view showing the service_type of the broadcasting signal.In the example of FIG. 32, 0x00 to 0x07 indicate reserved (0x00), analogtelevision (0x01), ATSC_digital_television (0x02), ATSC_audio (0x03),ATSC_data_only_service (0x04), software download data service (0x05),unassociated/small screen service (0x06), and parameterized service(0x07), respectively. In the example of FIG. 32, 0x08 to 0x0F indicatethe reserved regions. In the example of FIG. 32, 0x10 indicates thedigital television service type for the mobile service, 0x11 indicatesthe audio service type provided as the mobile service, and 0x12indicates the data service type provided as the mobile service. 0x14 to0x7F indicate the reserved regions and 0x80 to 0xFF indicate the userprivate regions. In the example of FIG. 32, the VCT may includeinformation about service_type for identifying the mobile receptionchannel and the fixed reception channel. The VCT including theinformation about the service_type for identifying the mobile receptionchannel and the fixed reception channel may be included in the mainservice data section and the mobile service data section and may betransmitted.

FIG. 33 is a view showing an example of generating the VCT including thevirtual channel information for the main service data and the mobileservice data and transmitting the VCT. For convenience of description,it is assumed that the example of the service transmitted through thevirtual channel is equal to that shown in FIG. 25.

In FIG. 33, the VCT for the main service data and the VCT for the mobileservice data may have the same PID (0x0FFB). As shown in FIG. 33, theVCT including the channel information of the main service data and themobile service data includes the channel information of the main servicedata and the mobile service data. The VCT may be transmitted through onephysical channel through which the mobile reception channel signal andthe fixed reception channel signal are transmitted (in one physicalchannel, transport_stream_id is equal. In FIG. 33,transport_stream_id=ttt1 (any number)). In example of FIG. 33, since thenumber of fixed reception virtual channels is 1 (num of channel=1) andthe number of channels included in the mobile reception virtual channelis 2 (num of channel=2), “num of channel” is 3 (=1+2).

With respect to the fixed reception virtual channel, the VCT includesinformation about a major channel (No. 30) and a minor channel (No. 1)and includes the modulation mode information (which may be 0x04 or 0x05in the example of FIG. 31) of the signal transmitted through the fixedreception virtual channel. The program number of the fixed receptionchannel of FIG. 33 is 1 and the service type thereof is 2 (0x02;ATSC_digital_television) and has the information about the service typeprovided to the digital television.

With respect to the fixed reception channel, theservice_location_descriptor of the VCT includes the video ES PIDinformation (0x31), the ES PID (0x34) of the Korean audio stream and theES PID (0x35) of the English audio stream.

With respect to the mobile reception channel, the VCT includes majorchannel information and minor channel information of the mobilereception virtual channel (30-5 and 30-6 in the example of FIG. 33).With respect to the mobile reception channels 30-5 and 30-6, the VCT maybe transmitted such that the modulation mode for the channel fortransmitting the mobile service data is included. Although themodulation mode is indicated by the mobile in FIG. 33, the example ofthe detailed value is shown in FIG. 31.

In the example of FIG. 33, the VCT may include 5 as the program numberof the channel 30-5, which is the mobile reception virtual channel, andincludes 6 as the program number of the channel 30-6. The VCT may havethe values shown in FIG. 32 as the value of the service type of themobile service data transmitted through the virtual channel (indicatedby the mobile in FIG. 33).

The service_location_descriptor of the VCT may include the ES PID (0x51)of the video stream, the ES PID (0x54) of the Korean audio stream andthe ES PID (0x78) of the data stream as the channel information of thechannel 30-5 which is the mobile reception channel. With respect to thechannel 30-6 of the mobile reception virtual channels, theservice_location_descriptor of the VCT delivers the ES PID of the streamincluded in the virtual channel 30-6. In the example of FIG. 33, theservice_location_descriptor may include the ES PID (0x61) of the videostream, the ES PID (0x64) of the Korean audio stream and the ES PID(0x65) of the English audio stream, with respect to the channel 30-6.The VCT including the information about the above-described fixedreception channel and mobile reception channel may be encoded by thePSIP encoder for the united PSI/PSIP with main and mobile service andmay be multiplexed with the mobile service data and the main servicedata, and the multiplexed data may be transmitted.

The program table information including the information about the mobileservice data and the main service data may be included in the process ofprocessing the mobile service data and the main service data in thetransmitter as shown in FIG. 3.

The program table information having the main/mobile service datainformation multiplexed with the mobile service data is subjected to apre-processing process by the pre-processor. Meanwhile, the programtable information having the main/mobile service data informationmultiplexed with the main service data is subjected to the process ofremoving a packet jitter. In addition, the VSB transmission signal framemay be formed by the post-processing process and may be transmitted.

Meanwhile, FIG. 8 shows the example where the mobile service data isincluded in the burst section in the unit of a group including 118segments. However, FIG. 8 is only exemplary and the mobile service datamay be distributed in the entire burst section. In this case, thebroadcast receiving system receives the mobile service data only in theburst section and receives the main service data in the non burstsection. As another example, the mobile service data group and the mainservice data group may be arranged at a ratio different from the ratioshown in FIG. 8 in one burst section and may be transmitted/received. Inthis case, if the broadcast receiving system wants to obtain only themobile service data (for example, if the broadcast receiving system forthe mobile reception channel or the broadcast receiving system for themobile/fixed reception channel wants to obtain the mobile service data),the mobile service data group may be processed within the burst section.The fixed broadcast receiving system may process the main service datagroup of the burst section and the main service data of the non burstsection.

FIG. 34 is a conceptual view of the reception of the mobile service dataincluded in the burst section while reducing power consumption. Thebroadcast receiving system can receive only the broadcasting signal inthe burst section because the broadcast receiving system is powered ononly in the burst section including the mobile service data of thevirtual channel which is desired to be viewed by the user (In theexample of FIG. 8, the main service data may be included in the burstsection. However, since the main service data may be processedindependent of the mobile service data or may be discarded, only themobile service data in the burst section may be processed). In thiscase, the united program table information which can describe the mainservice data and the mobile service data is received and processed inthe mobile service data section of the burst section. For example, ifthe first virtual channel (service 1 of FIG. 32) is desired to beviewed, the broadcast receiving system is powered on only in the burstsection including the mobile service data for the program of the firstvirtual channel and is powered off in the remaining signal section. Ifthe user wants to view the program of the second virtual channel, thebroadcast receiving system is powered on only in the burst sectionincluding the program of the second virtual channel and receives themobile service data for the second virtual channel. Accordingly, if theuser switches the channel from the first virtual channel to the secondvirtual channel, the section in which the broadcast receiving system ispowered on/off may be changed. If the broadcast receiving system ispowered on in the burst section, the multiplexed program tableinformation in the burst section can be obtained. The multiplexedprogram table information includes the multiplexing information for themain service data and the mobile service data, the channel information,and the broadcasting program information. That is, the program tableinformation may include the information describing the main service dataand the mobile service data. The program table information may furtherinclude the identifiers for identifying the mobile service data and themain service data.

FIG. 35 is a detailed view showing the case where the broadcastreceiving system can receive the mobile service data included in theburst section as the broadcasting signal while reducing powerconsumption. According to the example of FIG. 35, the virtual channels30-1, 30-5 and 30-6 may be included in one physical channel. Thedescription of the burst identifier (burst_id) is shown in FIG. 28.

As shown in FIG. 34, the broadcasting service according to the virtualchannel is multiplexed in a different burst section and thus the burstsection may have the identifier according to the virtual channelincluded in the burst section. The burst section or the burst identifierfor identifying the service data included in the burst section may bereceived from the signaling information of the broadcasting signal orthe descriptor (shown in FIG. 28) of the program table information suchas the VCT.

In the example of FIG. 35, the burst identifier of the mobile servicedata (service 1; S1) of the channel 30-5 is 1 (the main service data Mmay be included in the burst section) and the burst identifier of themobile service data (service 2; S2) of the channel 30-6 is 2 (the mainservice data M may be included in the burst section). In FIG. 35, sincethe main service data is not located in the burst section, the burstidentifier may not be set. In FIG. 35, it is assumed that the signal ofthe channel 30-6 is output when the broadcast receiving system ispowered on (a).

The broadcast receiving system can receive the program table informationfrom the broadcasting signal from a power-on time point a during apredetermined time period (b) regardless of the burst, in order toobtain the program table information including the channel informationin the broadcasting signal. For example, even when the signal of themobile reception channel is received, the broadcasting signal may becontinuously received until every channel information is obtained,regardless of the burst section or the non burst section. The broadcastreceiving system can obtain the same program table information from themain service data and the mobile service data. Accordingly, thebroadcast receiving system can receive more rapidly receive themultiplexing information such as the channel information included in theprogram table information. That is, since the broadcast receiving systemcan obtain the united program table information with respect to themain/mobile service from the main and mobile service data, it ispossible to more rapidly obtain the entire channel information. Thebroadcast receiving system can obtain the channel information of themobile/fixed reception channel and the PID information of thebroadcasting stream delivered through the channel from the unitedprogram table information.

At a time point (c) where the channel map is generated using the channelinformation, the PID of the broadcasting stream of the channel desiredby the user or the channel which should be originally output isselected, the broadcasting stream is decoded, and the decoded contentsare output. If the channel desired by the user is the mobile receptionchannel, the broadcast receiving system obtains the burst identifierincluding the mobile service data of that channel, is powered on (c, d)in the burst section and is powered off in the remaining signal section(d, e). The broadcast receiving system can output the broadcastingsignal and provide the broadcasting service from the power-on sectionaccording to the burst section. Accordingly, the broadcasting servicemay be output from a time point when the burst section of the channeldesired by the user starts.

If the broadcast receiving system receives the fixed reception channel,the broadcasting service of the channel desired by the user can beoutput immediately after the channel map is generated, regardless of theburst. The broadcast receiving system first may output the broadcastingservice using the channel map, which is previously stored, even beforethe channel map is generated and cope with the channel change of theuser after the channel map is generated.

FIG. 36 is a view showing an example of the broadcast receiving system.Referring to FIG. 36, the example of the broadcast receiving system willbe described. The example of the broadcast receiving system includes atuner 1100, a demodulator 1200, a demultiplexer 1300, a program tableinformation decoder 1400, a controller 1500, a decoder 1600, a memory1700 and an output unit 1800.

The tuner 1100 can receive the broadcasting signal transmitted throughat least one of the fixed reception channel or the mobile receptionchannel. That is, the broadcasting signal received by the tuner 1100 mayinclude the main service data and the mobile service data therein. Thetuner 1100 tunes the channel selected by the user and outputs thebroadcasting signal of the channel. The broadcasting signal receivedfrom the fixed reception channel may include a terrestrial/cablebroadcasting signal.

The demodulator 1200 demodulates the signal output from the tuner 1100and outputs the demodulated signal. The demodulator 1200 may demodulateat least one of the broadcasting signal of the fixed reception channelor the broadcasting signal of the mobile reception channel. For example,the demodulator 1200 may demodulate the 64 VSB/256 VSB modulation signalor demodulate 64 QAM/256 QAM modulation signal. The demodulator 1200 maydemodulate the broadcasting signal of the fixed reception channel andthe broadcasting signal of the mobile reception channel. The example ofdemodulating the mobile service data and the main service data is shownin FIG. 22 (refer to the operation and the description of FIG. 22excluding the tuner) in detail. The demodulator 1200 may not demodulatethe broadcasting signal according to the null packets, which aretransmitted so as to be matched to the transmission rate, in thereceived signal. In the example of FIG. 36, if only the mobile servicedata can be received, the demodulator 1200 may demodulate only themobile service data of the burst section and may discard the remainingmain service data. In contrast, in the example of FIG. 36, if both themain service data and the mobile service data are received, the bothreceived signals are demodulated and output. If the demodulator 1200demodulates at least one of the main service data and the mobile servicedata in FIG. 22, the demodulated data may include the program tableinformation describing both the main service data and the mobile servicedata. The program table information multiplexed with the demodulatedmain service data and the program table information multiplexed with themobile service data may be input to the program table informationdecoder 1400 through the demultiplexer 1300.

The demultiplexer 1300 may demultiplex the signal output from thedemodulator 1200 and output the demultiplxed signal. The demultiplexer1300 may directly receive the mobile service data stream or the mainservice data stream from an external device. For example, when thebroadcast receiving system can receive the broadcasting stream from thedigital VCR, the demultiplexer 1300 may directly receive and demultiplexthe broadcasting stream through a predetermined interface, for example,an interface having the IEEE 1394 format. The demultiplexer 1300 maydemultiplex the video stream, the audio stream and the program tableinformation in the received broadcasting stream. For example, if theprogram table information according to the examples of FIGS. 27 to 33 isincluded in the received signal, the demultiplxer 1300 outputs theprogram table information to the program table information decoder 1400and outputs the video and audio signals in the broadcasting signal tothe decoder 1600. That is, the demultiplexer 1300 may demultiplex theprogram table information including the multiplexing information of themain service data and the mobile service data and the broadcastingsignal and output the demultiplexed data. The demultiplexing unit 1300may demultiplex the program table information including the multiplexinginformation of the mobile service data and the main service data andoutput the demultiplexed information.

When a channel selection command is received from the controller 1500,the demultiplexer 1300 may output the video/audio stream according tothe video/audio PID of the channel selected by the user to the decoder1400.

The program table information decoder 1400 may decode the demultiplexedprogram table information and output the decoded information to thecontroller 1500. The program table information decoder 1400 may decodethe program table information including the multiplexing information ofthe mobile service data/main service data. In this case, the programtable information may include the identifiers for identifying the mobileservice data and the main service data. In the example of FIG. 36, theprogram table information decoder may decode the program tableinformation of the main service data and the program table informationof the mobile service data. If the program table information multiplexedwith the main and mobile service data is received, it is possible torapidly obtain the channel information.

The controller 1500 may control the components shown in FIG. 36 andstore the information about the channel using the received program tableinformation. For example, the controller 1500 may store the informationabout the video/audio/data stream of the channel in the channel map formusing the parsed program table information. For example, the controller1500 may store the channel map of the mobile service data and thechannel map of the main service data so as to be divided according tothe channel map form or may store the channel map of the mobile servicedata and the channel map of the main service data together. Here, theprogram table information may include both the main and mobile servicedata and include the identifiers for identifying the main service dataand the mobile service data.

The controller 1500 may receive a user control signal through a userinterface. When the user transmits the control signal such as thechannel change, the controller 1500 may output the signal of the channeldesired by the user by referring to the channel map information.Although the channel information of the mobile service data and thechannel information of the main service data are stored in one channelmap form, the controller 1500 may control the broadcasting signaltransmitted through each channel to be output. That is, the controller1500 may control the tuner 1100, the demodulator 1200 and thedemultiplexer 1300 such that the broadcasting signal of the channel isoutput, if the channel change between the virtual channels for providingthe main service and the mobile service or the channel change betweenthe virtual channel for providing the mobile service is made. Forexample, if a channel change command is received, the controller 1500may select the channel changed through the tuner 1100 by referring tothe channel map. The controller 1500 may control the demodulator 1200such that the signal of the channel selected by the user is demodulated.For example, if the user selects the mobile reception channel, thecontroller 1500 may control the demodulator 1200 such that only themobile service data in the burst section in which the mobile servicedata of the mobile reception channel is multiplexed is demodulated (thedemodulation operation of the demodulator may refer to the descriptionof the blocks shown in FIG. 22 excluding the tuner). If the user selectsthe fixed reception channel, the controller 1500 may control thedemodulator 1200 such that only the main service data is demodulated.The controller 1500 may control the demultiplexer 1300 such that thepacket of the broadcasting signal of the channel selected by the user isdemultiplexed according to the stored channel map.

The controller 1500 may control the power of the blocks shown in FIG.36. For example, if the broadcast receiving system shown in FIG. 36receives the mobile service data, the power of the broadcast receivingsystem may be controlled such that the signal is received only in theburst section including the mobile service data of the receptionchannel. Accordingly, although the broadcast receiving system receivesthe signal of the mobile reception channel, it is possible to reducepower consumption. The controller 1500 may obtain the identifier of theburst section from the descriptor of the program table information orthe signaling information. Accordingly, the controller 1500 may controlthe demodulator 1200 to demodulate only the burst section through theburst information indicating in which burst section the broadcastingsignal of the channel desired by the user is transmitted. The controllermay control the demultiplexer 1300 such that the broadcasting signalaccording to the PID of the broadcasting stream of the channel desiredby the user is demultiplexed.

Meanwhile, the controller 1500 may control the application or the userinterface of the broadcast receiving system of FIG. 36. The controller1500 may update and manage the channel map through the program tableinformation, control the tuner 1100 and the program table informationdecoder 1400, and operate a channel manager according to the channelrequest of the viewer. The channel manager may update the channel mapusing the program table information which is newly received and controlthe demultiplexer 1300 to select the PID of the video/audio stream ofthe channel desired by the user.

The decoder 1600 decodes the video and/or audio stream output from thedemultiplexer 1300 and outputs the decoded stream. For example, thedecoder 1600 may decode the audio stream encoded according to an AC-3 orthe video stream encoded by an MPEG-2.

The output unit 1800 may output the video/audio signal output from thedecoder 1600. In the example of FIG. 36, the output unit 1800 includes adisplay unit for outputting the video signal and a speaker foroutputting the audio signal. The output unit 1800 may display a graphicsignal generated by the controller 1500 and the video signal displayedon the screen by an on-screen display (OSD). The signal output fromoutput unit 1800 by the graphic signal includes a channel number,broadcasting program information, broadcasting station information, abroadcasting title, a broadcasting time, a caption, a broadcastingclass, and a detailed plot.

The memory 1700 may store data, such as channel information according tothe channel map, and application. For example, the memory 1700 may be anonvolatile random access memory (NVRAM) or a flash memory.

The signal demodulated by the demodulator 1200 may IP datagram. Forexample, referring to FIGS. 22 to 23, the packet output from the RSframe decoder of the demodulator 1200 may be the packet including the IPdatagram. Alternatively, in the example of FIG. 35, the digitalbroadcasting system may receive the IP stream including the mobileservice data through a network interface (not shown). In this case, thecontroller 1500 operates an IP manager such that the IP stream can betransmitted/received according to the IP and the IP stream can betransmitted/received according to the source and the destination of theIP stream. The controller 1500 operates a service manager such that aservice provided by the IP stream received through the IP manager can beoutput in real time, and the service manager may implement thevideo/audio received by the IP stream. For example, the service managermay control the service received by the IP protocol in real time. Forexample, if the service manger controls the real-time streaming data,the service data can be controlled using the real-time transportprotocol/RTP control protocol (RTP/RTCP). The IP stream may include theprogram table information describing the mobile service data and themain service data in addition to the video/audio. If the IP stream isdecoded, the process of the program table information is performed asdescribed above. Meanwhile, the controller 1500 may decode the data inthe received IP datagram and store the decoded data in the memory 1700.The controller 1500 may execute the application such that the datastored in the memory 1700 can be output or provided to the user.

FIG. 37 is a flowchart showing an example of receiving the broadcastingsignal. The example of receiving the broadcasting signal will bedescribed with reference to FIG. 37.

The user powers on the broadcast receiving system (S105).

The user selects a physical channel or changes a physical channel tunedpreviously (S110). The channel map is formed or, if the channel map ofthe channel included in the received signal is previously formed, thefrequency of the channel selected according to the channel map is tuned(S120). The tuner may output the best tuned result to the controller forstoring the channel map.

The tuned broadcasting signal is demodulated (S130). If the broadcastingsignal is demodulated, the broadcast receiving system which can receiveonly the main service data may not demodulate the mobile service data,that is, may discard the mobile service data as the null packets. Incontrast, the broadcast receiving system which receives the mobileservice data demodulates the signal according to the method formodulating the mobile service data. The detailed demodulating processmay refer to the example of FIG. 22. The broadcast receiving systemwhich can process both the main and mobile service data receives andprocesses the broadcasting data included in the burst section and thenon burst section.

The program table information is multiplexed and parsed from thedemodulated signal (S140). For example, after the PAT is received andparsed, the PMT information of the program may be parsed. Since theprogram table information is transmitted after being multiplexed withthe main and mobile service data, it is possible to obtain the sameprogram table information even when only the mobile service data can beprocessed, even when only the main service data can be processed or evenwhen both the main service data and the mobile service data can beprocessed. That is, the program table information includes the channelinformation of the main service data and the mobile service data andincludes the identifiers for identifying the main service data and themobile service data.

The information about the channel is obtained from the parsed programtable information and the PID information of the audio/video/data ES ofthe channel is detected (S150). For example, the VCT is received andparsed such that the information about the mobile reception channel andthe fixed reception channel can be obtained. If both the mobile servicedata and the main service data can be processed, the program tableinformation is obtained from data sections multiplexed respectively withthe mobile service data and the main service data. Accordingly, it ispossible to more rapidly collect the channel information compared withthe case where the program table information is obtained from one datasection.

The channel information detected in the step S150 is stored as thechannel map or the stored channel map is updated. The mobile receptionchannel is distinguished from the fixed reception channel using themodulation_mode and the service_type of the VCT or themobile_service_descriptor of the PMT.

It is determined whether the service such as the audio/video/data ES ofthe channel information received according to the channel selected bythe user is valid in the receiving system (S160). If the channel is notvalid (no in the step S160), for example, “no channel” or “no signal”may be displayed to the user according to the predetermined channeloperation (S165). In order to obtain the channel information of thevalid channel, the process may return to the step S140 such that newprogram table information is received (S167).

If only the main service data can be processed, the mobile receptionchannel can be processed as the invalid channel (that is, the processingprocess of “no” of the step 160 is performed). In contrast, if only themobile service data can be processed, the fixed reception channel can beprocessed as the invalid channel.

If the channel selected by the user from the output channel informationis the valid channel (yes in the step S160), the PID of theaudio/video/data stream of the virtual channel is selected according tothe channel map (S170). The demodulating process of the step S130 iscontrolled depending on whether the channel selected by the viewer isthe fixed reception channel or the mobile reception channel according tothe channel map. The process for demodulating the broadcasting signalreceived through the fixed reception channel and the mobile servicechannel may refer to FIG. 22.

The audio/video/data stream according to the demultiplexed PID isdecoded such that the broadcasting signal is output. If the main servicefor the fixed reception channel is provided, the broadcasting signal ofthe channel is successively subjected to the channel tuning,demodulating and demultiplexing processes such that the main servicedata is output. In contrast, if the mobile service according to themobile reception channel is provided, the broadcasting signal may beprocessed such that only the signal of the burst section including thebroadcasting signal of the mobile reception channel selected by the useris subjected to the channel tuning, demodulating and demultiplexingprocesses. When the broadcasting signal is output, the channel number orthe channel information selected by the OSD may be selectively displayedon the screen (S175).

The broadcast of the channel selected by the user is output (S180). Thevideo/audio/data stream of the broadcasting signal transmitted throughthe selected virtual channel is decoded and output. The user can view anormal broadcast and control the broadcast reception through the OSD.

While the broadcast is viewed, the physical channel or the virtualchannel may be changed (S190). If the physical channel is changed, thestep S110 is performed and, if the virtual channel is changed, the stepS170 is performed. If the channel is changed between the mobilereception channels or the channel is changed from the fixed receptionchannel to the mobile reception channel in the case where both the mainservice data and the mobile service data can be received, the step S170is performed such that the burst including the broadcasting signal ofthe changed channel is searched for and the broadcasting signal isdemodulated only in the burst section. In contrast, if the channel ischanged between the fixed reception channels or the channel is changedfrom the mobile reception channel to the fixed reception channel, thedata of the section including the main service data is demodulated (ifthe main service data is included in the burst section, the data of themain service data section including the burst section can bedemodulated).

However, if only the main service data can be processed, the mobileservice data is considered as the signal according to the null packetand thus the mobile reception channel cannot be selected or can beprocessed as the invalid channel although selected. If only the mobileservice data can be processed, the fixed reception channel is processedas the invalid channel.

If the channel is not changed, it may be determined whether the versionof the channel information is updated (S200). If the channel informationis updated, the information about the channel map is updated and thestep S140 is performed in order to receive the new program tableinformation. If the channel information is not updated, the step S180may be performed.

Hereinafter, FIG. 38 is a view showing a descriptor including theidentifier of the burst section, and FIG. 39 is a view showing anexample of delivering cell information for mobile reception to theprogram table information such as the PMT.

FIG. 38 shows the example of the descriptor including the identifier ofthe burst section for the virtual channel information in thebroadcasting signal transmitted/received by the method fortransmitting/receiving the broadcasting signal according to the presentinvention. In FIG. 38, for convenience sake, the above-describeddescriptor is called time_slice_information_descriptor. This descriptormay be transmitted as the descriptor included in the PMT or the VCT. Thetime_slice_information_descriptor includes a descriptor tag, adescriptor length, Burst_TS_id which is the identifier of the burstsection and offset information between the burst sections. The burstsections in the broadcasting signal may include the identifier accordingto the broadcast included in the burst section. The offset informationmay be offset information between the successive burst sections oroffset information between the burst sections in which the broadcast ofthe same channel is transmitted. In FIG. 38, the identifier in the burstsection including the broadcasting signal may be delivered and receivedand the broadcasting signal may be received according to the identifier.For example, the identifier of the burst section includes theidentifiers of the sections “S+M1” “S+M2” as shown in FIG. 34 and theoffset information between the burst sections may include the sectionsbetween the (c) and (e) or the sections (d) and (e).

FIG. 39 shows the program table information including the physicalchannel information for each cell in the program table informationtransmitted according to the embodiment of the present invention. Thephysical channel information transmitted from each cell (here, the cellindicates the region which can receive the broadcasting signal from anyone transmitter) may be transmitted by a network information table (NIT)of the PSI. Since the NIT includes the physical channel information forthe current cell and other cells, when any broadcasting stationtransmits the broadcasting signal according to the modulation method ofthe mobile service data, the NIT may also include the physical channelinformation of the broadcasting stations other than the broadcastingstation. In the example of FIG. 39, the PID of the packet transmitted bythe NIT is 0x010 and the table identifier (table_id) is 0x40. FIG. 39shows the case where only the channel information of two cells isdelivered for convenience of description. In the example of FIG. 39, theidentifier of each cell and the channel information of each cell areincluded in the cell frequency_link_descriptor of the networkdescriptor( ) The identifier of the first cell (cell_id) is 0x0001 andthe frequency of the first cell is 0x03aefe40 (fc=618 MHz), theidentifier of the second cell is 0x0002, and the frequency of the secondcell is 0x4a32240 (fc=778 MHz).

In the example of FIG. 39, the physical channel information of at leastone cell identified by the identifier of the cell may be providedthrough a transport stream loop (TS loop) of the NIT. In the TS loop,the service_list_descriptor for providing the list information of theservices according to the identifiers of the transport streams may beincluded. In the example of FIG. 39, since both the transport streamidentifiers (transport_stream_identifier) transmitted to the first celland the second cell are 0x901, the first cell and the second celltransmit the same transport stream. The NIT delivers the cellinformation including the physical channel information of the cell tothe broadcasting delivery system descriptor of each cell(terrestrial_delivery_system_descriptor( ).

In the example of FIG. 39, the information about the first cell fordelivering the transport stream may include the central frequency of thetransmitted signal (618 MHz; 0x03aefe40), the bandwidth (6 MHz; 010), anidentifier (time_slicing_indicator) indicating whether the signal can bereceived by a time slicing scheme according to the transmission of theburst signal, a modulation mode such as mobile VSB, a value indicating afirst error correction encoding rate (sccc_rate-HP_stream) for a highpriority channel, a value indicating a first error correction encodingrate (sccc_rate-LP_stream) for a low priority channel, a valueindicating a second error correction encoding rate(rs_code_rate-HP_stream) for the high priority channel, a valueindicating a second error correction encoding rate(rs_code_rate-LP_stream) for the low priority channel, and an identifier(other_frequency_flag) indicating whether the transport stream isbroadcasted to the cell.

In the example of FIG. 39, the information about the second cell fordelivering the same transport stream as the first cell may include thecell information including the physical channel information includingthe central frequency (778 MHz; 0x04a32240) of the transmission signal,the bandwidth (6 MHz; 010) and so on.

In the example of FIG. 39, the NIT transmitted from each cell includesthe information indicating through which physical channel all thetransport streams are transmitted from that cell to other cells. The NITtransmitted from any cell may transmit the cell information includingthe physical channel information for that cell and another cell, thatis, a cell adjacent to that cell. Accordingly, in the case where thebroadcasting signal receiving device is handed over from the first cellto the second cell, the same broadcasting signal can be received fromthe second cell and can be output although the broadcasting signalreceived from the first cell is received through another channel of thesecond channel. Upon handover, the user can continuously view thebroadcast of the same channel without additional channel searching.Meanwhile, in the example of FIG. 39, the descriptors transmittedthrough the NIT may be transmitted through the descriptor in the PMT.

The effects of the digital broadcasting system and the data processingmethod are as follows. According to the present invention, it ispossible to provide a digital broadcasting system and a data processingmethod, which are robust against channel change or noise. In addition,it is possible to improve reception capability of a reception system byperforming additional encoding processes with respect to mobile servicedata and transmitting the encoded mobile service data to the receptionsystem. In addition, it is possible to improve reception capability of areception system by inserting known data into a predetermined region ofa data region and transmitting the data by an appointment of atransmitter and a receiver. Furthermore, it is possible to transmitprogram table information for mobile service data and main service data.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of transmitting a broadcast signal in a transmitter, the method comprising: pre-processing first service data including audio data or video data for a mobile service via a preprocessor, wherein pre-processing the first service data comprises: block processing the first service data via a block processor, wherein block processing the first service data comprises: first converting data bytes of the first service data to data bits via a first converter; encoding the first converted data bits to output symbols via a first encoder; symbol interleaving the output symbols via a symbol interleaver; second converting the symbol interleaved symbols into data bytes of the first service data via a second converter; forming data groups via a group formatter, each data group including signaling information, known data sequences that have pre-determined values, and the first service data, wherein the signaling information includes information indicating a number of the data groups to be transmitted during a transmission frame, and forming first service data packets including data in the data groups via a packet formatter; multiplexing, via a multiplexer, the first service data packets and second service data packets, the second service data packets including second service data including audio data or video data for a main service; performing, via a second encoder, systematic Reed-Solomon (RS) encoding on the second service data in the multiplexed data packets and non-systematic RS encoding on the first service data in the multiplexed data packets; and transmitting a broadcast signal including the RS encoded first service data and the RS encoded second service data via a transmission unit, wherein a collection of the formed data groups is transmitted during slots in the broadcast signal, wherein the slots are basic time periods for multiplexing of the first service data and the second service data, and wherein the signaling information includes an identifier of the collection of the formed data groups.
 2. The method of claim 1, wherein: a code rate of the encoding of the first converted data bits is G/H; and G and H are integers.
 3. The method of claim 2, wherein the signaling information further includes information indicating the code rate.
 4. The method of claim 1, wherein the pre-processing further comprises first randomizing the first service data via a first randomizer, the method further comprising: second randomizing the second service data in the second service data packets and only a portion of the first service data packets via a second randomizer.
 5. An apparatus for transmitting a broadcast signal, the apparatus comprising: a pre-processor configured to pre-process first service data including audio data or video data for a mobile service, wherein the pre-processor comprises: a block processor configured to block process the first service data, wherein the block processor comprises: a first converter configured to first convert data bytes of the first service data to data bits; a first encoder configured to encode the first converted data bits to output symbols; a symbol interleaver configured to symbol interleave the output symbols; a second converter configured to second convert the symbol interleaved symbols into data bytes of the first service data; a group formatter configured to form data groups, each data group including signaling information, known data sequences that have pre-determined values, and the first service data, wherein the signaling information includes information indicating a number of the data groups to be transmitted during a transmission frame, and a packet formatter configured to form first service data packets including data in the data groups; a multiplexer configured to multiplex the first service data packets and second service data packets, the second service data packets including second service data including audio data or video data for a main service; a second encoder configured to perform systematic Reed-Solomon (RS) encoding on the second service data in the multiplexed data packets and non-systematic RS encoding on the first service data in the multiplexed data packets; and a transmission unit configured to transmit a broadcast signal including the RS encoded first service data and the RS encoded second service data, wherein a collection of the formed data groups is transmitted during slots in the broadcast signal, wherein the slots are basic time periods for multiplexing of the first service data and the second service data, and wherein the signaling information includes an identifier of the collection of the formed data groups.
 6. The apparatus of claim 5, wherein: a code rate of the first encoder is G/H; and G and H are integers.
 7. The apparatus of claim 6, wherein the signaling information further includes information indicating the code rate.
 8. The apparatus of claim 5, wherein the pre-processor further comprises a first randomizer configured to first randomize the first service data, the apparatus further comprising: a second randomizer configured to second randomize the second service data in the second service data packets and only a portion of the first service data packets.
 9. A method of transmitting broadcast data in a transmitter, the method comprising: identifying null data packets in an input stream including the null data packets that contain null data and broadcast service data packets that contain at least broadcast service data for a broadcast service or first signaling data for signaling the broadcast service; deleting the identified null data packets in the input stream, wherein the first signaling data include information for indicating a type of the broadcast service and information for indicating whether the broadcast service is hidden; encoding data in the broadcast service data packets to add parity data; encoding second signaling data including transmission parameters at a code rate, wherein the transmission parameters include information to identify a number of the parity data; block interleaving the encoded second signaling data; convolutional interleaving the data to which the parity data are added; and transmitting a broadcast signal including the convolutional interleaved data and the block-interleaved second signaling data.
 10. The method of claim 9, wherein the first signaling data further include major channel information and minor channel information of the broadcast service.
 11. A transmitter for transmitting broadcast data, the transmitter comprising: a demux to identify null data packets in an input stream including the null data packets that contain null data and broadcast service data packets that contain at least broadcast service data for a broadcast service or first signaling data for signaling the broadcast service, and delete the identified null data packets in the input stream, wherein the first signaling data include information for indicating a type of the broadcast service and information for indicating whether the broadcast service is hidden; a first encoder to encode data in the broadcast service data packets to add parity data; a second encoder to encode second signaling data including transmission parameters at a code rate, wherein the transmission parameters include information to identify a number of the parity data; a first interleaver to block interleave the encoded second signaling data; a second interleaver to convolutional interleave the data to which to parity data are added; and a transmitting unit to transmit a broadcast signal including the convolutional interleaved data and the block-interleaved second signaling data.
 12. The transmitter of claim 11, wherein the first signaling data further include major channel information and minor channel information of the broadcast service. 